For Forest tree improvement

1. Provenance and species trails
• Concept:
• Biological material is unique in its variability
• Considerable differences or variation for a
particular character among population growing
together on different sites and among the trees
of the same populations.

2. Species trails
• Selection of few species well suited for the purpose and
well adopted for the site
• Trail conducted to know test the species on different
sites to determine their suitability for those traits.
• When large number of species: species trails are
conducted in phases
• Initial trails are conducted on small sized plots for a
shorter period followed by statistically valid trails with
large plot size for longer period to identify the most
suitable species.

3. Different phases of species trails
• Species selection may pass through a number of trial
stages that eventually will end in the selection of a few
provenances of a few species well suited for the
purposes and well adapted for the areas in question.
• The stages may be as follows:
Species elimination trials
Species testing phase/growth trials
Species proving phase/pilot plantations

4. Species elimination trials
• Objective: To compare the performance of a large
number of different species on one or more number of
sites and to select smaller number of species.
• Individual species unit kept small
• Duration; for a short period (1/10 to 1/5 rotation) to
determine survival and promise of reasonable growth
• Where a large number (20-40) of possible species is
tested in small plots on one or a few sites.
• Continued introduction of small number of species are
often made over a number of years.

5. Species testing phase
 Objective: Comparison of restricted number of promising species selected
on the basis of previous experiments on sites within a broad climatic
region.
 aslo called as adoptability phase
 Where a reduced number (5-10) of promising species are tested and
compared in larger plots for longer periods(1/4 - 1/2 rotation).
 Sites will be stratified in order to evaluate the interaction between site
variation and species differences.
 Statistical designed layouts
 Duration of longer period
 5-10 promising species are selected from elimination phase and tested in
larger plots.

6. Species proving phase
• Objective: is to confirm the superiority of a few probable species.
• Species may be different for different sites: Those shown themselves
superior in earlier phases included in the testing under normal
plantation conditions.
• Needs statistically valid experimental design
• Should include blocks, replication, randomization, plot size and
buffer trees etc.
• Plots must be large enough to provide data
• eliminate the edge or boarder effects

9. Provenance trails
• Background: The choice of seed sources is one of the main
factors affecting the establishment and productivity of
plantations of forest trees.
• In the present practice of silviculture, provenance research
provides a sound basis for the selection of seed sources.
• Anyone concerned with afforestation and reforestation
should develop a program of provenance research to assist
in the selection of seed sources.
• Provenance research should be given highest priority at the
outset of any program of forest tree improvement.
• Information on provenance is important in assuring
sources of seed to give well-adapted, productive trees and
in directing breeding of interracial and interspecific hybrids
toward adaptation to particular localities

10. • Provenance: in forestry refers to the population of trees
growing at a particular place of origin or geographic area
from which the forest reproductive/seed source is
obtained.
• Provenance research defines the genetic and
environmental components of phenotypic variation
associated with geographic source.
• Provenance trails; means forest seed source collected
from several provenances kept separately identical and
planted together in an experiment design at each of
several sites.
• Provence testing is essential for species that occur over a
wider geographical or ecological ranges.

11. • Purpose of provenance trails
a. Mapping the pattern of racial variations if any
b. To delineate the boundaries of provenances.
c. Matching the genotypes with provenance
Phases of provenance trails
For species with wide distribution, the selection of provenances
may go through a number of phases:
(1) a range-wide provenance sampling phase,
(2) a restricted provenance sampling phase and
(3) a provenance proving stage

12. Range-wide provenance phase; To determine the extent and
pattern of variability among provenances of a species.
• Depending on the size of geographical distribution and
climatic variation the species range, 10-30 provenances are
suggested.
• This phase is concurrently runs with species testing phase
Restricted provenance phase: s designed to identify smaller
regions and finally individual provenances that have the
greatest productivity
• Less variation between plots of selected provenances, plot
interactions will be smaller, and therefore plot; size could be
decreased. (Large plots are only required where plot
interactions are expected to be great.)
• This phase run concurrently with species proving phase

13. • Provenance proving stage: A small number of probably useful
provenances are tested at this stage under normal plantation
conditions.
• Whereas in the first two phases careful attention must be given
to experimental design, in the proving phase this aspect is less
important
• Replication of sample plots within and between proving plots
is essential. Proving plots are large.
• Experimental designs:
RCBD and incomplete block design and Lattice design
• Evaluation of species and provenance trails
 Evaluation in nursery
 Evaluation in Field