SITKA SPRUCE CONTINUOUS COVER MANAGEMENT  Pro Silva Ireland VISIT TO WALES-Pembrokeshire/CarmarthenshireSeptember 2017

1. SITKA SPRUCE CONTINUOUS COVER MANAGEMENT
Pro Silva Ireland VISIT TO WALES-Pembrokeshire/
Carmarthenshire
September 2017
A REVIEW OF 20 YEARS IRREGULAR SIVICULTURE
PERFORMANCE
IN PRIVATE FORESTRY
UPLAND SPRUCE PLANTATIONS

2. • Overview: CCF latest review and possible
transformaJon pathways in Ireland
• PresenVng the results of 15/20 years irregular
Silviculture in two SS private stands of
25ha and 700ha in Wales
• Key take home points and quesVons for
further research

3. Overview
• CCF development is currently supported by NaVonal
and European Forestry Policy with increasing “grass
roots” interest BUT sVll less then 1% applicaVon in
pracVce (public and private)(Vitkova, 2014) .
-perceived as complicated by foresters
-lack of visible examples for owners
-lack of clear transformaJon roadmap with user
friendly inventory
- lack of models for Vmber forecasVng for saw millers
- some operaVonal and markeVng uncertainVes

4. Overview: CCF and broadleaves
Loosely linked to future management of Broadleaves plantaVons (30.000 ha)
especially NaVve Woodlands:- environmental landscape sensiVviVes
-Windfirm Sites
-Moderate YC

5. Overview: CCF and Sitka Spruce
• Clearfell dominance
• Can private Sitka Spruce plantaJons be managed commercially other than with clear fell/
replant ?
• CCF pilot sites
• Mineral soils

6. Overview
Silvicultural Systems: Sawlog producVon systems
as conVnuum
Clearfell : Narrow sawlog producVon window
from Premature felling (40-60% sawlog)
to full rotaVon (70-80% sawlog) (photo from Ireland et al, 2006)
Irregular Siviculture
PROSILVA Silviculture:
Shelter Wood : ConVnuous sawlog producVon
Extended sawlog producVon window

7. TransformaVon paths:
focus on progressive transformaVon
)
Figure adapted
from
Sanchez,2011

8. Progressive TransformaVon mimics
Natural Succession stages
• Stage 1-PreparaJon thinning
(stem exclusion stage)
• Stage 2-ReducJon of tot BA/ha
to promote natural regeneraVon
(understorey reiniVaVng stage)
• Stage 3-Structural development
(all sized)
• Stage 4-Structural maintenance
(all sized):
• When a good structure is achieved
(sustained yield, natural tree
replenishment and ecosystem
resilience), maintain the structure by
removing the increment mostly from
large trees.
equilibrium
Species Age/years ATer thin
BA/m²
Before thin
BA /m²
Spruce Stage 1 up to 35-40 31 36.5-39
Spruce Stage 2 up to 45-50 27 32-34
(figure from Kerr and Haufe, 2011)

9. Equilibrium Basal area distribuVon and
thresholds
Small Trees Medium Trees Large Trees+ Very Large
Trees
10-25% 30-50% 45-60%
Figure from Sanchez, 2017

10. No long term SS study but exisVng N.Spruce European case studies
The Reinenger System Shlag monastery, Austria
Despite removals of 73, 59, 55 and 70 m³/ha (mostly saw log) over last 20 years the
standing volume has increased from 378 to 415m³ /ha while the stand is increasing in
standing value and developing a desired structure
Figure and table from Bangor University, 2015
See also
Lähde et al, 2001; Sterba and Zingg ,2001;
Price and Price, 2006

11. Site one : Coed Preseli , Tŷ Rhŷg
• Coed Preseli is owned by
Bob & Jill Holding, who
have run a local business
for over 50 years, and
have invested in local
forests. The forest is
comprised of six separate
forests situated in the
Preseli Mountains near
Rosebush,
Pembrokeshire.

12. Tŷ Rhŷg
• Area =25 ha Species SS
• Soil =podsol
• ElevaVon= 200-300m
• Yield class= 16
• Bough in 2001
as 300m³/ha 40% sawlog
standing ( tot 7850 m³)
low biodiversity, no ground flora.
• If clearfelled then it would be
now 17 year old spruce at first
thinning stage.

13. Tŷ Rhŷg
• Since 2001 7549m³ harvested in 5
intervenVons
• Standing sale basis 50-70 m³/ha
2002 40% sawlog
2007 50% sawlog
2011 60% sawlog
2015 windblown single
trees and small groups
2017 85% sawlog
70 tonnes per ha
average trees size
1.5 m3 = 46 trees /ha
@ 40-50cm dbh
• ConvenVonal harvest system with racks 18m
apart and planning to move further apart
using chainsaw/harvester system
• Current standing volume 300-350 m³/ha @
70-80% sawlog
• Current Stocking 350 trees/Ha
• @ 45 trees removal per ha per intervenJon
= current standing trees removed in 40
years

14. Tŷ Rhŷg
• Natural regeneraVon
plus enrichment
planVng of WRC and DF
• Rich ground flora
• Bird diversity typical of
NaVve oaks (wood
warblers, redstarts and
both species of
flycatchers)

15. Site two:Bryn Arau Duon
• Similar management system to
previous site
• SS planted in 1962-87
• 700 ha on peaty podsols
@200-450m elevaVon 1800mm
rainfall
• Yield class 16-18
• In an environmentally sensiVve
area
• IniVal thinning carried out using
graduated density system (see
new PhD project)
• Some clear-felling management
integrated on the higher /less
stable locaVons

16. Bryn Arau Duon
• In the Last 17 years
100.000 m³ of Vmber
harvested of which 5000
m³ from clearfell
• 1 million sterling value
• Sawlog % and standing
value increasing
• Stability also increasing
• Natural regeneraVon with
enrichment planVng WRC
• Red squirrel populaVon
and ground flora diversity
increasing

17. Key Discussion points
• Sites were less than opVmal and yet to
date seems to be performing.
• The importance of regular inventory to
instruct and guide management. The need
to define and test cost effecVve
monitoring protocols.
• Future Stability : Can be an issue at Juvenile stage but
seems to improve as stocking lowers and soil ecology develops
• Possibility of IntegraVon with clearfell
• Future markets for large sawlog : sawmills can take
up to 60 cm dbh but can be an issue for larger trees.
• The system seems therefore most suited to
mid low yield class SS (20 YC and less)

18. Key Discussion points
• Enrichment planVng is both desirable
and affordable
• Too much natural regeneraVon can be
expensive to manage: do NOT create
large gaps in the canopy.
• The need for trained harvesVng
contractors and good communicaJon
with forester.
• The need for long term inventory data
to validate new CCF yield models (see
first point) for Vmber forecasVng
• Resiliance

19. Thank you