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Effect of root growth potential, planting distance and provenance of Gmelina arborea
 

Effect of root growth potential, planting distance and provenance of Gmelina arborea

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    Effect of root growth potential, planting distance and provenance of Gmelina arborea Effect of root growth potential, planting distance and provenance of Gmelina arborea Document Transcript

    • ASIA LIFE SCIENCES 21(1): 1-18, 2012 The Asian International Journal of Life Sciences Effect of root growth potential, planting distance and provenance on the growth and survival of Gmelina arborea Roxb. ONOFRE S. CORPUZ1* and WILFREDO M. CARANDANG2 The study was conducted in Matalam, Cotabato Southern Philippines to test the effect of root classes, provenance and distance of planting on early field survival and growth of Gmelina. The experimental design used in the study was a strip-split plot design with three replications. Analysis of variance revealed significant differences in the growth of Gmelina after one year. Strong genetic control over height, basal area, and biomass were found. This result was supported by the positive and significant relationship of provenance with the same traits. Seeds from Quezon were significantly different in terms of merchantable and total height compared to Cotabato and Davao del Sur seed sources. While in terms of basal area and biomass, Quezon and Cotabato did not differ significantly. On the other hand, the three provenances did not vary significantly in terms of diameter breast height (dbh), tree volume and survival. Distance of planting also insignificantly affects height, diameter growth and survival of the tree. However, basal area, tree volume and biomass varied significantly. Root classes affected tree diameter, total height, survival rate, and volume significantly. All factors did not show variation on basal area, and merchantable height. Root classes were found to be positively and significantly correlated with dbh, basal area, root and total tree biomass. Key words: germination, survival rate, seed provenance, planting distance, root classes, growth, tree volume, Philippines 1 Departmen of Forestry, College of Agriculture, Cotabato Foundation College of Science and Technology, Doroluman Arakan, 9417 Cotabato Philippines. *Corresponding author 2 Institute of Renewable Natural Resources (IRNR), College of Forestry and Natural Resources (CFNR), University of the Philippines Los Baños, College 4031, Laguna, Philippines. Received 06 March 2011; Accepted 30 May 2011. ©Rushing Water Publishers Ltd. 2012. Printed in the Philippines
    • Corpuz & Carandang 2012 INTRODUCTION In the Philippines, many studies on seedling attributes dealt with morphological traits. Only a few studies investigated root growth in relation to field planting performance. Root growth potential (RGP) is seldom used as a measure of seedling quality. Elsewhere, studies were done chiefly on temperate tree species such as Pinus radiata (Rook 1971), Sitka spruce (Deans et al. 1990), Douglas-fir (Cannel et al. 1990, Sharpe & Mason 1992, Rose et al. 1991, Hasase & Rose 1994), Loblolly pine (Larsen et al. 1986, Williams 1972, Fere & Krebs 1985), Slash pine (McGrath & Duryea 1994) and Ponderosa pine (Stone & Jenkinson 1959). Gazal (1998) studied the root growth potential of Narra (Pterocarpus indicus Willd.) transplants as influenced by moisture level. Methods of measuring RGP have already been standardized in many temperate countries but this has not been done in the tropics including the Philippines (Gazal 1998). The potential of using RGP as an indicator of seedling quality and performance of one important tree species in the Philippines needs to be explored. This study attempted to provide a basis for interpreting RGP and early field performance of Gmelina arborea Roxb., one of the most common exotic tree species used for reforestation and industrial tree plantation in the country now. The relationship between root system development of planted forest tree species and its survival, stability and growth has gained considerable research interest (Van Eerden & Kingshorn 1978, Coutts & Lewis 1983, Deans & Ford 1983). Seedlings established naturally have been found to have a stable root configuration with well developed tap roots and evenly distributed lateral roots, whereas bare root transplants were often less stable having irregularly distributed root system (Chavasse 1978, Burdett 1979a). High root growth capacity of plants and planting stock has been reported to have improved survival after field planting and growth rates (Stone & Jenkinson 1970, Burdett 1979, Sutton 1980, Burdett et al. 1983, Burdett et al. 1984). RGP must be capable of being interpreted on site, relating physiological attributes to the conditions of the intended field environment would aid allocating stock to plantations. The use of on-field interpretations of RGP has not been tested under well-defined field environments. That is, planting stocks with high RGP are expected to survive and perform better on sites than those with low RGP. Seedlings with low RGP are assumed to be more prone to damage under harsh environmental conditions than those with higher RGP. Seedling performance in the planting site depends on its growth potential and the degree to which conditions in the area allow its growth potential to be expressed. The degree to which seedlings are conditioned to the environment in the planting site will have the greatest influence on their performance immediately after planting. Thus, foresters and nurserymen should come up with a planting stock assessment procedure that anticipates prevailing conditions in the area to be planted. The few planting stock assessment schemes being done in the country considers the top of seedlings as the basis for judging their quality. Seedling tops are very visible and top growth can easily be manipulated by nursery techniques (Carandang 1994). Thus, with these schemes, the quality of planting stocks is usually evaluated 2 Asia Life Sciences 20(1) 2011
    • Growth and survival of Gmelina primarily through height, root collar diameter, and top/root ratio. Again, these characteristics or measurements can be readily altered by nursery practices. In an industrialized country, emphasis is now being given to the roots as the basis for judging seedling quality. A new scheme has been developed for the grading of nursery seedlings which considers the RGPs of seedlings. There is a growing body of evidence that support the notion that the number of lateral roots upon lifting the seedlings from the nursery directly affects the survival and growth of the same after field planting (Carandang 1994). The RGP of a seedling reflects the seedling’s ability to initiate and elongate roots when it is placed into an environment favorable for root growth (Ritchie 1985). RGP has been considered to be positively correlated to seedling survival and growth (Burdett et al. 1983, McCleary & Duryea 1987). This study sought to determine the suitability of RGP in evaluating seedling field performance under Philippine conditions using G. arborea, one of the most commonly used exotic species for tree plantation in the country. Other variables considered in the test included the effects of distance of planting, and provenance. The objectives of this experiment were: (a) to determine the effect of RGP on field performance and survival of G. arborea species; (b) to evaluate the suitability of RGP as a measure of seedling quality through actual field trials as affected by distance of planting, and provenances; (c) to test whether RGP of Gmelina arborea is closely related to stem and other root morphological characteristics and (d) to determine the family mean heritability of first order lateral root (FOLR) of the species. MATERIALS AND METHODS The seeds of Gmelina from three provincial sources such as Quezon, Cotabato, and Davao del Sur were raised in the nursery of Arakan, Matalam, Cotabato. After 60 days, the seedlings are carefully lifted from the seed bed and washed with running water throughout to remove excess soil particles. Number of FOLRs developed were counted to establish root groupings for Gmelina by provenance. The seedlings with three root groupings established such as R1 (0-10), R2 (11-20) and R3 (21-30+) by provenance were immediately outplanted in the field at different spacing arrangement, namely: 2 x 2 m, 2 x 3 m and 2 x 4 m following a strip-split plot design with three replications. The experiment was established in a 1.021 ha. cogonal field of Arakan Matalam, Cotabato (Figure 1) in November 6, 2006. The area of the plots were varies according to distance of planting. The 2 x 2 m had 756 m2 area, 2 x 3 m had 1134 m2 and the 2 x 4 m had an area of 1512 m2. The soil in the experimental site is silty clay with pH value ranging from 6.2-7.2. The soil nitrogen is low with moderate phosphorus and potassium content. The rainfall recorded during the conduct of the study was 2,084.6 mm. The highest amount was obtained in June (378.9 mm) while the lowest was in February (51.52 mm). Collection of data started after 30 days was undertaken monthly afterwards throughout the duration of the study. Stem diameters and heights were measured. Six months after outplanting of the seedlings, corn were inter-planted but data analysis disregarded the effects of the annual crops on the growth and survival of the Gmelina tree. Asia Life Sciences 20(1) 2011 3
    • Corpuz & Carandang 2012 Figure 1. Map showing the study site - Matalam, Cotabato Province, Mindanao, Philippines. Data analysis. Analysis of variance and regression procedure were employed in the analysis of data using SAS software for faster and appropriate data analysis and interpretation. The field performance of the tree species in terms of height and diameter as affected by root classes, distance of planting, provenance and interactions of all variables were statistically calculated using strip-split plot design analysis of variance. The presence or absence of G x E interactions in all morphological characters of the plants was determined from the resulting ANOVA. Family mean heritability of all seedlings morphological characters were estimated based on the analysis of variance of plot means. The narrow sense heritability is computed using the following equation derived from ANOVA: h2 = MSF - MSFxR MSF (1) where: h2 = narrow sense heritability; MSF = mean square value for family; MSFxR = mean square value for family by replication interaction 4 Asia Life Sciences 20(1) 2011
    • Growth and survival of Gmelina RESULTS AND DISCUSSION Survival rate. The rate of Gmelina trees survived in the field after one year revealed no significant differences among provenances and distance of planting. However, survival rate was significantly different in terms of root classes (Figure 2). The survival rate of Gmelina trees belonging to root classes 2 and 3 were significantly higher than those in root class 1. Landis and Skakel (1988) claimed that RGP tests do not predict actual planting performance as they predict only the survival potential of the seedlings. Thus, the more new roots developed in a seedling, the better potential for growth and survival. This was supported by the study of Feret and Kreh (1985) which said that one of the preconditions for the survival and rapid growth of transplants after outplanting is a high RGP. A capacity for root growth will not only mean that the root system is active or alive but also effectively capable of absorbing water and nutrients. Thus, RGP provides a measure of the functional integrity of the whole plant (Ritchie 1984). Figure 2. Survival rate of Gmelina as influenced by (a) provenance; (b) root classes and (c) distance of planting. RGP is not limited to its predictive ability to determine the potentials for field survival but the health and vigor of the seedlings as well. Blake et al. (1989) reported the relationship between outplanting survival and stem diameter for Douglas-fir. They found that the relationship between survival and diameter was affected by seedling root mass, especially for smaller diameter seedlings. Seedling with good root mass consistently survived better that those with poor root mass (Mexal & Landis 1990). Height and shoot size are poor indicators of seedling survival; however, if the seedling survives, initial height has been shown to be linearly related to further height growth in some species (Mexal & Landis 1990). Root collar diameter on the other hand is a better indicator of survival and performance partly because it is related to the size of the root system and partly because a large stem diameter makes the seedling sturdier and increases the stem Asia Life Sciences 20(1) 2011 5
    • Corpuz & Carandang 2012 area available for water transport. Studies with Loblolly pine have shown survival and growth to be positively correlated with seedling diameter (South et al. 1989). Sturdiness quotient or the ratio of height to root collar diameter, is a combination of two traits used as a stock quality test in New Zealand (Hawkins, undated). Hashizume and Han (1993) showed that the height of Sawtooth oak (Quercus acutissima Carruth) seedlings was an important factor in determining growth and survival, with the tallest trees (>150 cm) having lower survival percentage than trees 100-120 cm in height. The amount of new roots developed after field planting determines the initial survival of the seedlings. Hence, the threshold RGP value critical for the stock to achieve its field performance potential must be established per seedling. Simpson et al. (1988) proposed an RGP threshold value of 0 root greater than 10 mm in length per seedling as a batch culling guidelines for several Northwest conifer species (Landis & Skakel 1988). The same threshold value was also suggested by British Columbia for interior spruce and lodgepole pine (Ritchie & Tanaka 1991). It was further recommended that threshold values should also be determined for other species for which positive correlation between RGP and field performance has been found threshold values may vary among planting sites and year. Using a stochastic model, it may be possible to define RGP level with 95% confidence for any planting site and year. The said model would be able to specify the nursery cultural practices, lifting dates, cold storage and field handling and planting procedures needed to attain the required RGP for successful field performance (Feret & Kreh 1985). Tree height. The trend of the monthly height growth of Gmelina up to one year followed a typical sigmoidal behavior (Figure 3). Abrupt growth was observed during the start of the rainy season in June. The monthly height growths of the trees from the different seed sources were significantly different in terms of provenance up to one year. Height in terms of distance of planting was only significant up to the 10th month and became insignificant afterwards. On the other hand, height differences as affected by root classes was significant up to the 6th month but became insignificant in the succeeding months. The interaction effects of the provenance x distance of planting (F x D) were consistently significant up to the 10th month but insignificant differences appeared on the 11th to 12th months. Provenance x root classes (F x R) interaction was significant up to the 9th month but became insignificant during the 10th to 12th months. Merchantable height revealed significant differences in terms of provenance but not in terms of distance of planting and root classes. The trees from Quezon were significantly higher with those from Davao del Sur and Kabacan, Cotabato (Table 8). Total height revealed significant differences in terms of root classes. Root classes 3 and 2 are significantly different with root class 1. Provenance and distance of planting did not show significant variations in terms of total height growth of Gmelina. Data from Jacobs and Siefert (undated) indicated that FOLR was a poor predictor of height growth of northern red oak, white oak, and black cherry (Prunus serotina Ehrh.) after 1 year. In the sweetgum research of Belanger and McAlpine (1975), stated 6 Asia Life Sciences 20(1) 2011
    • Growth and survival of Gmelina that the growth response of various root collar diameter grades was obvious after the first growing season and continued through the seventh season. At that point, trees from the largest seedling grade averaged 1.95 m (6.4 ft) taller than trees from smaller grade. For the interaction effects, only F x R revealed a significant result, the rests were all insignificantly varied. Figure 3. Monthly height growth of Gmelina as affected by provenances, planting distance and root classes. Tree diameter. The monthly diameter growth trend of the Gmelina tree one year after field planting was shown in Figure 4. Abrupt growth started in April four months after field establishment with the occurrence of slight rain. The cultivation of the field in preparation for the planting of corn could have triggered this rapid growth. Diameter growth of Gmelina in the field revealed significant results in terms of provenance and planting distances up to one year. The diameter in terms of root classes revealed no significant differences up to the 8th month. However, in the 9th to 12th month the differences became significant. The environmental factors which contribute significantly to the overall make-up of the plant constitute major differences in RGP among seedlings even of the same species (Landis & Skakel 1988). Seedlings with large robust root systems have the best opportunity to achieve early competitive position (Ruehle and Kormanik 1986). Although a robust root system is normally associated with desirable stem characteristics, large stems themselves are not necessarily related to robust roots and competitive ability after outplanting (Feret & Kreb 1986). Asia Life Sciences 20(1) 2011 7
    • Corpuz & Carandang 2012 Figure 4. Monthly diameter growth of Gmelina as affected by provenances, planting distance and root classes. The interaction effects of F x D consistently significant up to the 12th month. F x R and D x R interactions were not significant up to the 4th month but significant on the 5th month. There interactions became insignificant in the 6th month but significant result reappears again on the 7th up to 12th month. The interaction effect of the distance of planting x root classes (D x R) is significant on the 8th to 10th months but in the rest of the months there was no significant differences. The number of FOLR has been shown to be positively related to seedling competitiveness both in the nursery and after outplanting and has been a highly heritable trait with some species (Kormanik 1986b, Kormanik et al. 1990). Analysis of variance reported a significant result of dbh of Gmelina after one year in the field in terms of provenance and root classes. However, distance of planting is insignificantly different in dbh. Cotabato and Quezon provenances were significantly different from Davao del Sur. The root classes on the other hand reported that root class 3 is significantly different with root classes 1 and 2 (Table 1). RGP is found to affect seedling morphology as well as physiology ( Cannell et al. 1990) in their research which indicated that high sturdiness ratio, root:shoot ratio, root collar diameter, root lengths and volumes which have been traditionally associated with high seedling stock quality apparently gave high RGPs. 8 Asia Life Sciences 20(1) 2011
    • Growth and survival of Gmelina Table 1. Means1 of dbh, merchantable height and total height as influenced by provenance. Provenances dbh Merchantable height Total height Davao del Sur Candelaria, Quezon Cotabato Province 4.19516854a 6.62504505a 6.84514851a 2.39460674a 3.45414414b 2.76594059c 3.86146067a 5.26441441b 4.68742574a Planting distance 2x2m 2x3m 2x4m 5.86547368a 5.91300000a 6.14707547a 2.84189474a 2.76880000a 3.10405660a 4.53031579a 4.55240000a 4.86632075a Root classes 0 -10 11-20 21-30 & up 5.91138298a 5.91467290a 6.11570000b 3.04925532a 2.85000000a 2.84310000a 4.77436170a 4.57271028b 4.63380000b 1 Means with the same letter are not significantly different at 5% level of significance. These results indicated that RGP is a superior measure of seedling quality as compared to standard morphological traits used before (Feret & Kreh 1985). But this does not mean that other morphological attributes are not important for maintaining seedling quality, rather the difference in physiological quality can cause more variation in RGP than the morphological characteristics by which seedlings are currently being graded (Larsen et al. 1983). Stone et al. (1962) pointed out that there were physiological differences in seedling grown from the same or different nursery. Hence, it was further suggested that physiological grade of seedlings should be evaluated vis a vis other seedling quality information (Landis & Skakel 1988). The interaction effects of all factors were found insignificantly different in terms of dbh growth of Gmelina trees in the field. Basal area. The Gmelina trees differed significantly in basal area growth in terms of provenance and distance of planting while root classes and interactions of all factors were found insignificant. Quezon and Cotabato were significantly different with Davao del Sur provenance (Table 2). The 2 x 2 m tree spacing was significantly higher with 2 x 3 m and 2 x 4 m tree spacing. Stem diameter according to Dey and Parker (1997) is a best predictor of growth. Computation of the basal area considered the density of tree per hectare, does more density of tree means higher basal area. Interactions of all factors were insignificantly affects the basal area of the tree in tons/ha. Tree volume. Tree volume reported an insignificant result in terms of provenance, but significant on distance of planting and root classes. The 2 x 2m tree spacing was significantly higher in volume compared to the other two planting distances (Table 3). This is true because the computation is per hectare basis so that stand density is Asia Life Sciences 20(1) 2011 9
    • Corpuz & Carandang 2012 Table 2. Means1 of basal area (m2/ha) as influenced by the three factors: provenances, distance planting and root classes. Provenances Means Davao del Sur 10.0796935a Quezon 25.0388559b Cotabato 24.9222823b 1 Distance of Planting 2 x2m 2x3m 2x4m Means 27.6022816a 19.7542062b 15.0558384c Root classes Means 0-10 19.4923923a 11-20 20.6161062a 21-30+ 21.5534801a Means with the same letter are not significantly different at 5% level of significance. Table 3. Means1 of volume (cu.m/ha) as influenced by the three factors: provenances, distance planting and root classes. Provenances Means Davao del Sur 0.66064842a Quezon 1.30257138a Cotabato 0.84223270a 1 Distance of Planting 2 x2m 2 x3m 2x4m Means 1.29193174a 0.83650665b 0.77419298c Root classes Means 0-10 0.92724126b 11-20 0.92475517b 21-30+ 1.02952880a Means followed by the same letter vertically per factor are not significantly different at P>F. considered. More tree stand is found on closer spacing; does volume on 2 x 2m tree spacing is obviously higher as compared with the wider spacing. However, this finding is acceptable only at one year old Gmelina plantation. Root classes on the other hand, reported root class 3 as significantly higher with root class 2 and 1. Interactions of all factors were found insignificantly different on tree volume. Biomass. The analysis of variance for the estimated above ground, root and total tree biomass showed a significant result on all parameter considered. Cotabato and Quezon provenances were significantly higher with Davao del Sur in terms of above ground and root biomass. However, for the total tree biomass, provenance from Cotabato was significantly higher as compared with the other two provenances which are insignificant to each other (Table 4). Interactions of the three factors reported no significant differences in all parameters estimated. This finding can be explained by the positive and significant correlation of provenance with heights and biomass of one year old Gmelina. In this study, height and biomass can be viewed as highly influenced by provenance. Experiment of Ruehle and Kormanik (1986) with northern red oak showed that within a family, desirable stem characteristics of half-sib progenies were consistently associated with large numbers of FOLR. Frequency distributions of seedlings from three white oak mother trees were similar when seedling populations were stratified by FOLR with diameter greater than or equal to 1mm at the proximal end (Kormanik, Ruehle & Muse 1989a). 10 Asia Life Sciences 20(1) 2011
    • Growth and survival of Gmelina They further concluded that the root collar diameter, height and top and root weights of trees increased from the lowest lateral roots class (0 – 3 roots) to the highest class (>21 roots). In loblolly pine, the same group of scientists computed the frequency distributions and heritability of FOLR for seedlings progenies of 37 mother trees (Kormanik, Ruehle & Muse 1986b). Their findings indicated significant differences in all measured seedling parameters from the smallest to the largest FOLR class. If the frequency distribution of seedlings with strong root systems is genetically controlled and if strong root systems are excellent indicators of field performance as evidenced in the above mentioned studies, tree breeders may have several important implications (Carandang 1994). It maybe necessary, for instance, to change the ways in which individual seedlings are selected for progeny tests. It may also possible to removed one source of variation from tests by using only the progeny that has a satisfactory lateral root development, and it maybe desirable to select trees that produce high proportions of progeny with superior root systems. Table 4. Means1 of AGB (tons/ha), root biomass (tons/ha) and total tree biomass (tons/ha) as influenced by provenance, distance of planting and root classes. Provenances AGB Root Biomass Total Tree Biomass Davao del Sur Quezon Cotabato Province 1.86651719a 5.07619071b 5.12120667b 0.64214383a 1.56790656b 1.55668264b 2.50866102a 6.31966747b 6.66614853c Planting distance 2 x2m 2 x3m 2 x4m 5.55108295a 3.96281552b 3.04891170c 1.73137664a 1.23963333b 0.94310625c 7.28245959a 4.83047358b 3.99201795c Root classes 0-10 10-20 21-30+ 3.89959370a 4.15148312b 4.36048570b 1.22383184a 1.29280048b 1.35043533b 5.00605289a 5.31592612b 5.58661856b 1 Means followed by the same letter vertically per factor treatment are not significantly different at P>F In terms of distance of planting, the 2 x 2 m tree spacing was significantly higher compared to the two other spacing arrangements (Table 9). 2 x 3 m as well is significantly different with 2 x 4 m in all parameters computed. Lauridsen and Kjaer (2002) reported that the total standing biomass (kg/ha) and productivity of G. arborea at spacing 2 x 2 m was higher compared to 3 x 3 m plant spacing. For the root class, it was found that root class 3 is consistently higher and significantly different compared to root class 1 but not to root class 2 (Table 9). Asia Life Sciences 20(1) 2011 11
    • Corpuz & Carandang 2012 Interactions of the different factors were observed to be insignificant in all parameters computed. Family mean heritability estimates. Narrow sense heritability estimate is used for the growth trait of Gmelina after one year in the field. All traits were found relatively high. From Figure 5, highest genetic control appears to be in Root Biomass (h2 = 0.998) followed by merchantable height (h2 = 0.997), basal area (h2 = 0.982), above ground biomass (h2 = 0.979), total tree biomass (h2 = 0.970), volume (h2 = 0.784) and the lowest is DBH (h2 = 0.767). The mean square values used in the computation of the respective heritability values of seedling traits is in Appendix Table 37 to Appendix Table 45. Tree height in the field trials reported to be highly controlled genetically than dbh (Figure 2). This finding confirms that genetically determined variation exists in root system of plants (Street 1957). Brisette (1990) recognized that genetics plays a critical role in determining root system development of forest trees, both in the nursery and in outplanting. The number of FOLR has been shown to be positively related to seedling competitiveness both in the nursery and after outplanting and has been a highly heritable trait with some species (Kormanik 1986b, Kormanik et al. 1990). Heritabilty Estimate 1 0.8 0.6 0.4 0.2 0 DBH MH TH BA Volu RB AGB me TB Heritabilty 0.767 0.987 0.852 0.982 0.784 0.998 0.979 0.97 Tree Growth Figure 5. Family mean heritability of Gmelina from 3 provinces in the Philippines after 1 year in the field. 12 Asia Life Sciences 20(1) 2011
    • Growth and survival of Gmelina Kormanik (1986) contended that while stem diameter maybe considered a better estimator of seedling vigor, it cannot explain many of the differences in seedling performance after outplanting. Webb (1969) earlier cautioned against using stem diameter when comparing early plantation performance of sweetgum seedlings from the same family if they are grown in different seedling bed densities. This is because of the fact that stem diameter represents a seedling’s response to edaphic conditions. Nursery cultural conditions such as seedling bed density, fertility, moisture and mycorrhizal conditions have been shown to affect stem diameter. Unfortunately, the edaphic conditions that stimulate stem diameter increases are not found in the field. Kormanik’s study on sweetgum revealed that the distributions of seedlings among root grades remained relatively constant within an open pollinated mother tree seedlot. This finding led to his recommendation that seedling grading based on lateral root morphology maybe a practical way to identify the seedlings with the best potential (Carandang 1994). Regression and Correlation analysis. The effect of provenance and distance of planting on RGP of Gmelina had been determined through regression and correlation analysis of RGP in terms of root classes and root biomass across tree growth performance as affected by various factors considered in the study. Provenance of Gmelina tree revealed significant relationship with merchantable height, basal area, roots, above ground and total tree biomass (Table 5). With the exemption of dbh and volume, provenance has significant regression in most tree characteristics. This is supported by the positive and significant relationship of provenance with heights, basal area, agb, root and total tree biomass (Table 5). Distance of planting did not show significant regression with all tree characters measured. This result is supported by the poor relationship of distance of planting with all tree characters considered in the study. Dbh, basal area, root and total tree biomass revealed significant relationship with root classes (Figure 6) while, all parameters measured were significantly related with root biomass (Table 6). Thompson and Schultz (1995) found a negative correlation between initial height and first-year growth of northern red oak (Quercus rubra L.), while the number of FOLR was positively and significantly correlated with height, diameter growth, and survival. In contrast, initial height of Konara oak (Quercus serrata Thunb.) in Japan was positively associated with survival and weight after 5 years (Matsuda 1989). Data from Jacobs and Siefert (undated) indicated that FOLR was poor predictor of height and diameter growth of Northern red oak, white oak, and black cherry (Primus serotina Ehrh.) after one year. Stem diameter, shoot length, and number of FOLR were correlated with second year height and diameter of Northern red oak 2 years after planting in Ontario, with initial stem diameter being the best predictor (Dey & Parker 1997). Stem diameter was also a good predictor of many root system traits such as volume, area and dry mass. This is consistent with the study of Williams (1972) that showed stem diameter as better predictor of black walnut growth than root fibrosity. In the sweetgum research of Belanger and Mc Alpine (1975), stated that the growth response of various root Asia Life Sciences 20(1) 2011 13
    • Corpuz & Carandang 2012 Figure 6. Path correlation analysis (Pearson’s) across RGP, DBH, AGB, heights and biomass. collar diameter grades was obvious after the first growing season and continued through the seventh season. As revealed in the correlation analysis, the root classes are likewise correlated significantly with basal area, biomass and dbh. Root biomass on the other hand, showed a significant regression with all variables considered in the study (Table 6). Figure 6 presents a correlation path analysis across all traits of tree growth. As a measure of root growth potential (Stone & Schubert 1959, Burdett 1979), the number of lateral roots is now finding wide use in physiological grading of forest nursery seedling stocks. The results of the analysis indicated that the RGP in terms of root class and root biomass of Gmelina tree was positively associated with the other growth traits and characters. Similar to the result of this study, Thompson and Schultz, (1995) found that the number of FOLR was positively and significantly correlated with diameter growth, heights and growth of trees such as basal area and volumes. It can be said therefore that the use of RGP as an expression of seedling quality finds merit in its positive correlations with the other growth traits considered in the study. All morphological features specifically height and stem diameter, currently provide the best estimate of seedling performance after outplanting (Mexal and Landis 1990). Diameter is considered to be one of the best predictor of field survival while 14 Asia Life Sciences 20(1) 2011
    • Growth and survival of Gmelina height seems to predict height growth in plantation (Ritchie 1984). Root classes are highly correlated with biomass production as the findings of this study indicate support to Mexal and Landis (1990). Nevertheless, root morphology, specifically number of FOLR, finds much use with the trend towards the use of root growth potential as an indicator of early field performance and subsequent growth (Larsen et al. 1986, Ritchie & Dunlap 1980). The positive correlation of root classes with stem and growth characters was found to be highly significant in this study. Operational experiences tended to indicate that, other factors being equal seedlings with large stem calipers or diameters outperform those with smaller ones (Chavasse 1990, Cleary et al. 1979, Sutton 1979). When seedlings were carefully lifted as what has been done in the study, stem diameter were closely related with number of FOLR. At harvest, large diameter seedlings have more primary laterals (Rowan 1986). While it is possible that large diameter seedlings inherently have a more fibrous root system, it is more likely that smaller seedlings have thinner primary lateral roots that are more easily stripped during lifting operations (Carandang 1994). The improved field performance ascribed to larger diameter may partially, be the result of decreased root stripping. Blake et al. (1989) found that the relationship between field survival and seedling diameter was also affected by root mass especially for smaller diameter seedlings. Seedlings with good root mass consistently survived better than those with poor root mass. The positive correlation of root classes with stem diameter and seedling height has some physiological basis too. Evidences from the works of Richardson (1957, 1958) point to the fact that lateral root initiation and growth are influenced by both nutritional and hormonal factors derived from the shoot. SUMMARY AND CONCLUSION Performance of Gmelina in the field for one year showed strong genetic control over height, basal area, and biomass. The seeds from Quezon were significantly different in terms of merchantable and total height compared to Cotabato and Davao del Sur seed sources. Quezon and Cotabato seed sources did not differ significantly on basal area and biomass. Distance of planting insignificantly affects heights, diameter growth and survival rate of the trees. However, basal area, tree volume and biomass varied significantly. Two x 2 m tree spacing was significantly different with 2 x 3 m and 2 x 4 m. Root classes on the other hand, affected diameter, heights, percent survival, and volume significantly. Root class 3 is significantly differs with root classes 2 and 1 in terms of dbh. However, root class 3 did not show significant variation with root class 2 in terms of total tree height and volume. The three factors did not show variations on basal area, and merchantable height. Root classes was found to be positively and significantly correlated with dbh, basal area and root biomass. RECOMMENDATIONS A similar study should be undertaken to validate the result of this study. It was revealed in this study that variations in root and stem characteristics exist among the Asia Life Sciences 20(1) 2011 15
    • Corpuz & Carandang 2012 three provenances of G. arborea. A study should be conducted to determine if such variations will be evident also among the other sources of seeds of the species. Only Cotabato province has two locations considered in this study. Continuous gathering of data should be made to validate if the findings of this study is true in the long run. Effort should be put into identifying provenances that perform well in many trials rather than only in one or in a few. Kabacan, Cotabato and Candelaria Quezon seed sources of G. arborea is recommended for plantation in particular place in Arakan, Matalam, Cotabato. ACKNOWLEDGMENTS This work was funded by the Commission on Higher Education (CHED), Quezon City through Faculty Development Program and the Cotabato Foundation College of Science and Technology. The authors wish to thank the following: (a) Dr. Makalutang B. Luna, President of the Cotabato Foundation College of Science and Technology for his encouragement;(b) the family members of the first author: Ina and Papa, brother and sister, his loving wife and kids and (c) above all to most merciful and most beneficent Allah who made this work possible. LITERATURE CITED Belanger, R.P. and E.R.B. McAlpine. 1975. Survival and early growth of planted sweetgum related to root-collar diameter. Tree Planters’ Notes 26: 1-21. Burdett, A.N. 1979. New methods of measuring root growth capacity: their value in assessing Lodgepole stock quality, Canadian Journal of Forest research. 9: 63: 67. Burdett, A.N. 1987. Understanding root growth capacity, theoretical considerations in assessing planting stock quality by means of root growth tests. Canadian Journal of Forest Research. 17: 768- 775. Cannel, M.G.R, D.M. Tabbush, J.D. Deans, M.K. Hollingsworth, L.J. Shippard, J.J. Philipson and M.B. Murray. 1990. Sitka spruce and Douglas-fir seedlings in the nursery and in cold storage: root growth potential, carbohydrate content, dormancy, frost hardiness and mitotic index. Forestry 63(1): 9-27. Carandang, W.M. 1994. Lateral root development and seedling performance of large leaf mahogany (Swietenia macrophylla King). Ph.D Thesis, University of the Philippines Los Banos, College, Laguna. (unpublished) Chavasse, C.G.R. 1978. The root form and stability of planted trees with special reference to nursery and establishment practices. British Columbia Ministry of Forest /Canadian Forest Service Department Report 8. Chavasse, C.G.R. 1990. Planting stock quality. A review of factors affecting performance. New Zealand Journal of Forestry 25: 144-171. Cleary, B.D., R.D. Greaves and R.K. Hermann. 1979. Regenerating Oregon’s Forests. Oregon State University Extension Center, Corvallis, Oregon, USA. Coutts, M.P. and G.J. Lewis. 1983. When is the structural root system determined in Sitka spruce? Plant and Soil 71: 155-160. Deans, J.D. and E.D. Ford. 1983. Seasonal pattern of radial growth and starch dynamics in plantation-grown Sitka spruce trees of different ages. Institute of Terrestial Ecology, Bush Estate Penecuik, Midlothian, Scotland, EH 26 OQB. Deans, J.D., C. Lundberg, M.G.R. Cannel, M.B. Murray and L.J. Sheppard. 1990. Root system fibrosity of Sitka spruce transplants: relationship with root growth potential. Forestry 63(1): 1-7. 16 Asia Life Sciences 20(1) 2011
    • Growth and survival of Gmelina Dey, D.C. and W.C. Parker. 1995. Morphological indicators of stock quality and field performance of red oak (Quercus rubra L.) seedlings underplanted in a central Ontario shelterwood. New Forests 14: 145-156. Duryea, M.L. and K.M McClain 1984. Altering seedling physiology to improve reforestation success. In: Huryea and Brown (eds). Seedling Physiology and Reforestation Success. Martinus Nijhoff/Dr. W. Junk Publishers, The Hague, Netherlands. van. Eerden, E. and J.M. Kinghorn. 1978. Proceedings of the Symposium on Root form of planted trees. BC Min. Forest/Canada Forest Service. Report No. 8, Prov. British Columbia, Min. Forest, Victoria, British Columbia, Canada, 357 p. Feret, D.D. and R.E. Kreb. 1985. Seedling root growth potential as an indicator of loblolly pine field performance. Forest Science 31(4): 1005-1011. Gazal, R.M. 1998. Effect of soil moisture and root growth potential of narra (Pterocarpus indicus Willd.) transplants. M.Sc. Thesis, University of the Philippines Los Banos, College, Laguna. (unpublished) Hasase, D.L. and R. Rose. 1994. Root volume and growth of Ponderosa pine and Douglasfir seedlings. A summary of the eight growing season. Western Journal of Applied Forestry12(3): 69-73. Hashizume, H. and H. Han.1993. A study on reforestation using large-size Quercus acutissima seedlings. Hardwood Research 7: 1-22. Hawkins, C.B.D. and W.D. Binder.1990. State of the art seedling stock quality tests based on seedling physiology, pp. 19-21. In: Rose, R., S.J. Campbell and T.D. Landis (Eds.). Target Seedling Symposium: Proceedings, combined meeting of the Western Forest Nursery Associations; 1990 August 13-17; Roseburg, OR. Fort Collins (CO): USDA Forest Service, Rocky Mountain Forest range Experiment Station. General Technical Report RM-200. Kormanik, P.P. 1986. Lateral root morphology as an expression of sweetgum seedling quality. Forest Science 32(3): 595-604. Kormanik, P.P. and H.D. Muse. 1986. Lateral roots: a potential indicator of nursery seedling quality. TAPPI, 28 September 01- October 1986. Kormanik, P.P., J.L. Ruehle and H.D. Muse. 1989. Frequency distribution of lateral roots of 1-0 barsroot white oak seedlings. Research Note SE-353, USDA Forest Service, Southeastern Forest Experiment Station, USA. Kormanik, P.P., J.L. Ruehle and H.D. Muse. 1990. Frequency distribution and heritability of first-order lateral roots in lobloly pine seedlings. Forest Science 36(3): 802-814. Landis, T.D. and S.G. Skakel. 1988. Root growth potential as an indicator of outplanting performance: Problems and perspective. Proceedings, combine meeting of the western Forest Nursery Association; Western Forest Nursery Council; Forest Nursery Association of British Columbia; and international Forest Nursery Association. 8-11 August. Vernom, British Columbia, Canada. Larsen, H.S., D.B. South and J.M. Boyer. 1986. Root growth potential, seedling morphology and bud dormancy correlates with survival of Loblolly pine seedlings planted in December in Alabama, Tree Physiology 1: 253-263. Lauridsen, E.B. and E.D. Kjaer 2002. Site index equation for smallholder plantations of Gmelina arborea in Leyte Province, the Philippines. Small-scale Forestry Journal 7(1): 87-93, March 2008, Springfield, Netherlands. Matsuda, K. 1989. Survival and growth of konara oak (Quercus serrata Thunb) seedlings in an abandoned coppice forest. Ecological Restoration 4: 309-321. McCreary, D.D. and M.L. Duryea. 1987. Predicting field performance of Douglas-fir seedlings: Comparison of root growth potential, vigor, and plant moisture stress. New Forests 1: 153-169. Asia Life Sciences 20(1) 2011 17
    • Corpuz & Carandang 2012 Mexal, J.G. and T.D. Landis. 1990. Target seedling concepts; height and diameter. pp. 77-36. In: Rose, R., S.J. Campbell and T.D. Landis (Eds.). Proceediungsof the Target Seedling Symposium, Combine meeting of the Western Forest Nursery Associations, August 13-17, 1990. Roseburg, Oregon USDA Forest Service. Rocky Mountain Forest and range Exp. Sta. Gen. Technical Report RM 200, USA. Ritchie, G.A. 1984. Assessing seedling quality, pp. 243-260. In: Duryea, M.L. and T.D. Landis. (Eds.). Forest nursery manual: Production of bare root seedlings. Martinus Nijhoff/ Dr. W. Junk Publishers, Boston, MA, USA. Ritchie, G.A. 1985. Root growth potential principles, procedures and predictive ability. In: Duryea, M.L. (Ed.). Evaluating seedling quality: principle, procedures and predictive abilities of major tests. 93 -104. College of Forestry, Oregon State University, Corvallis, Oregon, USA, October 16-18, 1984. Ritchie, G.A. and J.R. Dunlap 1980. Root growth potential: Its development and expression in forest tree seedlings. New Zealand Journal of For. Sci. 10: 218-248 Ritchie, G.A., Y. Tanaka, R. Meade and S.D. Duke. 1993. Field survival and early height growth of Douglas-fir rooted cuttings: relationship to stem diameter and root system quality. Forest Ecology and Management 60: 237-256. Rook, D.A. 1971. Effect of undercutting and wrenching on growth of Pinus radiata Don seedlings.The Journal of Applied Ecology, 1971-JSTOR Rose, R., M. Atkinson, J. Gleason and T. Sabin, 1991. Root volume as agrading criterion to improve field performance of Douglas-fir seedlings. New Forests 9: 195-209. Rowan, S.J. 1986. Seedbed density affects performance of slash and loblolly pines in Georgia. In: South, D.B (Ed.) International Symposium on nursery management practices for the southern pines. Alabama Agricultural. Station, Auburn University, Auburn, Alabama, USA. Ruehle, J.L and P.P. Kormanik. 1986. Lateral root morphology: a potential indicator of seedling quality in northern red oak. Asheville (NC): USDA Forest Service, Southeastern Forest Experiment Station. Research Note SE-344, 6 p. Simpson, D.G.. and G.A. Ritchie. 1996. Does RGP predict field performance? A debate. New Forests 13: 249-273 Sharpe, A.L. and W.L. Mason. 1992. Some methods of cold storage can seriously affect root growth potential and root moisture content Forestry 1992 - Inst. Chartered Foresters. Stone, E.C. and G.H. Schubert. 1959. Root regeneration by Ponderosa pine seedlings, lifted at different time of the year. Forestry Science 5: 322 -332. Stone, E.C., J.L. Jekinson and S.L. Krugman. 1962. Root regenerating potential of Douglasfir seelings lifted at different times of the year. Forest Science 8: 288-297. Sutton, R.F. 1979. Planting stock quality and Grading. Forest Ecology and Management 2: 123-132. Thompson, J.R. and R.C. Schultz. 1995. Root system morphology of Quercus rubra L. planting stock and 3-year field performance in Iowa. New Forests 9: 225-236. Webb, C.D. 1969. Uniform seedling density is important in hardwood progeny test nurseries. In: Proceeedings of the 10th Southern Conference on Forest Tree Improvement, 17-19 June 1969, Houston, Texas, USA. Williams, R.D. 1972. Root fibrosity proves significant in survival, growth of black walnut seedlings. Tree Planters’ Notes 23: 22-25. Beyond Excellence © 18 ASIA LIFE SCIENCES Asia Life Sciences 20(1) 2011