final biog

Word count: 3000 Exam No: Y1475719

Environmental controls on Temperate Woodland: past, present and future perspectives.

INTRODUCTION

Disturbances, both human-induced and natural, shape forest biomes’ ‘composition, structure and functional processes’ (Dale et al¸2001). Emerging evidence suggests anthropogenic land-cover conversion and increasing carbon dioxide atmospheric concentrations - with projected global temperatures of as great as 5.8 º by 2100 due to emissions of greenhouse gases (Intergovernmental Panel on Climate Change, 2013) - are already altering some physical and biological systems (Thuiller et al, 2004 and Pearson and Dawson, 2003). A demonstration is the upward movement of high-mountain alpine and nival vegetation of the Alps into higher vegetation belts, (Pauli, Gottfried and Grabherr, 2014).

‘Landscape fragmentation as an anthropogenic activity has been considered a dominant driver of landscape dynamics’ and severe environmental consequences (Bucini and Lambin, 2002). A prime example is the relict of Kakamega forest of western Kenya. The spatial distribution of forest fragments (see Appendix A) is the result of pressures from human population densities; with resulting forest loss (table 1), trophic cascades and reduced

diversity (Yeshitela, 2008). Every forest stand is different, having different capabilities and environmental ranges – so respond differently.

From modern management in Europe, drastic changes in forest ecosystem structure and function are evident (Kouki et al. 2001; Kuuluvainen, 2002 in Brumelis et al, 2011). Burton

Table 1 Change in Area of Forest Fragment 1933 to 2001 of of the ancient Guineo-Congolian rainforest.

Fragment

Area (ha) in 1933

Area (ha) in 2001

Malava 703 190Kisere 458 420Kakameg 23,632 8,537

Source: BIOTA East Africa – Phase I Final Report

The decrease in forest landcover due to anthropogenic-induced stress in of the ancient Guineo-Congolian rainforest.

Figure 1: The geographical and topographical location of Beverley in Britain through Google Earth projections: SD 776785 at an elevation of 51m.

Source: Modified Google Maps & Digimap.


Bushes is situated westwards of the small market town, Beverley, of the East Riding of Yorkshire county in northeast Britain, figure 1 (Boatman, 1971). Located on Westwood, a 600 ac low-lying pastureland (see figure 1). It is a relict, managed sessile-oak dominated woodland (figure 2) covering 12 ha, which has natural origins

which exceed 200 years (Boatman, 1971). This low-lying deciduous woodland - between 53º50’N Latitude and 0º26 W Longitude (LatLong.net) - is regarded as a good reflection of woodland characteristics of Holderness Till soils (figure 3) (Boatman, 1971).

Due to the decline of ancient woodland in Britain and being deemed ecologically and socially important, Burton Bushes was designated a Site of Special Scientific Interest (SSSI) in 1980 (Woodland Trust, unknown date). It was secluded from grazers in 1981 - to facilitate regeneration - which were responsible for the bare or grass-dominant woodland floor and disrupting natural succession (Boatman, 1971). Grazers created sparsely populated fragments where woodlands once were. The second aim of management was to maintain the number of large, old oak trees (Boatman, 1971).

Abiotic and biotic environmental controls are in effect in Burton Bushes; the spatial distribution of successional stages through the wood due to the influence of ungulate grazing directly influence the biotic controls, such as soil fertility, competition, predation, canopy and shrub protection (Vera, 2000). Quercus petraea is the alpha tree layer in Burton Bushes; found in siliceous substrates in northern Britain (1973 Botanical Society of the British Isles, in Pears, 1977). It is a foundation species (Dahl, 2007); with a range of understory tree species including Betula pubescens, and Fraxinus; Ilex aquifolium has a dominant presence in the shrub layer (Boatman, 1971).

Figure 3: The location of Beverly on the Holderness Till.

Source: British Regional Geology, East Yorkshire and Lincolnshire (1948) in Catt, 2007.


Temperatures in this oceanic-dominated climate of East Riding (Boatman, 1971) reach an average of 8-10°C during spring months, see figure 4 (WMO, unknown), with an average of 31mm rainfall monthly, according to Yorkshire’s the Climate Change Plan (CCPYH). Yorkshire is already experiencing climatic changes - from 1960 to 2006 daily mean temperature rose by 1.5°C (Met Office, 2012) - and annual rainfall reduction projections of 6% by 2050. In response the CCPYH in 2010 designated Land Management a priority area for the future to manage the land appropriately and resiliently to changing conditions.

The aim of this investigation was to gain an understanding of the factors controlling vegetation composition and distribution today in Burton Bushes.

METHODOLOGY

2.1 Sample site

The observations for this study were obtained in said temperate deciduous woodland in the spring (late Feb-early March) of 2015.

2.2 Sampling Technique

Stratified sampling along two line transects was used to sample cross sections of the forest and the immediate perimeter. Tᵃ sampled from the arable pasture land in the NW direction to the grassland in the SE direction and Tᵇ sampled from the recreational land at the SW corner to the recreational field in the NE direction. Sixteen quadrat samples were collected along each transect, (figure 5) with 25 metre sampling intervals. A quadrat was sampled outside the fence surrounding the wood at the beginning and end of transects. The quadrats on Tᵇ 25m from either side of the woodland centre were sampled with a 20m² quadrat because the true centre was inaccessible. In each quadrat, all standing trees above or equal to breast height (1.3 meters) were identified, and diameters were measured in centimetres using girthing tape and estimates of each height in meters was measured. The division of labour was consistent throughout data collection to minimise human error in sampling.

Figure 4: The average daily (24h) temperature range per month in the East Riding of Yorkshire, from the period of 1961-1990.

Source: WMO

Figure 5: The placement of the sampling transects on Burton Bushes.

Source: Modified Digimap


2.3 Data Analysis

The quantative data was collaborated and graphs and tables made in Microsoft Excel. Tree ages were calculated using a formula derived from the Forestry Commission. Statistical tests were carried out in SPSS.

RESULTS

For raw data see Appendix B.

3.1 Tree richness and abundance variation

Tree species richness is the greatest at 75m DFC, with 6 species; but it is high from 25-125m DFC. It declines rapidly at 150m DFC with two species, and outside the managerial fence, one species. Abundance generally decreases with DFC, from 54 to 4 trees; Ilex aquifolium has the greatest abundance up to 100m DFC. Minimal difference in tree abundance is observed at 50m and 75m.

Table 2 ANOVA results of the relationship between tree species richness and DFC.

Tᵃ Tᵇp Value 0.057 0.370R² 0.029 0.006

There is no relationship between the DFC and tree species richness; the p-value for Tᵃ and Tᵇ both exceed 0.05, respectively 0.057 and 0.370. The R² present that only 2.9% and 0.6% of the tree richness can be explained due to DFC for Tᵃ and Tᵇ respectively.


0 20 40 60 80 100 120 140 1600

5

10

15

20

25

30

R² = 0.895626822157434

Figure 6: Ilex aquifolium frequency variation along Tᵃ

Ilex aquifolium

Linear (Ilex aquifolium)

Distance from Centre (DFC) (m)

Num

ber o

f Ind

ivid

ual T

rees

There is a strong negative correlation with Ilex aquifolium density and DFC along Tᵃ. Therefore, Ilex aquifolium density declines towards the woodland perimeter.

Table 3 ANOVA results of the relationship between Ilex aquifolium density and DFC.

The p-value<0.05, showing a significant relationship between Ilex aquifolium density and DFC. Furthermore, the R² shows that 84.7% of the species distribution can be explained by DFC.

25 50 75 100 125 1500

5

10

15

20

Figure 7: Frequency of Quercus petraea from the woodland centre

Fre-quency of Quer-cus pe-traea

Distance from the centre (DFC) (m)

Freq

uenc

y

Quercus petraea density increases with DFC, although experiences a rapid decline 50m-100m DFC off 13 trees. Density rapidly increases from 100m to 125m by 16 trees.

p-sig Value 0.09R² 0.847


3.2 Girth associations

25 50 75 100 125 1500

50100150200250300350400

Figure 8: Tree girth range variation with dis-tance from centre (DFC) (m)

Girth Range (cm)

Distance from center (DFC) (m)

Tree

Girt

h R

ange

(cm

)

There is a positive correlation with tree girth range and DFC. Girths increase at a slower rate 50-125m DFC.

25 50 75 100 125 150 1750

50100150200250300350400450

Figure 9: Girth range of Ilex aquifolium and Quercus petraea from the woodland centre

Girth (cm) Ilex aquifolium

Linear (Girth (cm) Ilex aquifolium )

Distance from centre (DFC) (m)

Grit

h ra

nge

(cm

)

In general Quercus petraea tree girths increase with DFC. At 75m DFC Quercus petraea girth reduces rapidly 190cm to 87cm, from which it steeply increases. Ilex aquifolium in general decreases, with a significant fluctuation at 75m DFC – experiencing steep increase of 101cm from 50m DFC. It then proceeds to decline.


3.3 Age associations

25 50 75 100 125 150Distance from centre (DFC) (m)

0

50

100

150

200

250

Figure 10: Tree Age distribution from the woodland centre

Tree

Age

(yea

rs)

There is a weak positive relationship between tree age and DFC – indicated by the interquartle ranges (IQR=UQ-LQ) increase with DFC; although there was significant variation at each site, particularly 50m and 100m. At 25m relatively consistently young trees ages were present - demonstrated by the small IQR of 32 years. The tree ages at each distance are negatively skewed, with greater numbers of younger trees. The most consistent tree ages were at 25m and 75m from the centre. There is significant overlapping between each distance and tree ages; 25m and 150m display the greatest difference in tree age range, respectively 3-176 years and 38-423 years.

25 50 75 100 125 150 1750

50100150200250300350400450500

Figure 11: Average age of Ilex aquifolium and Quercus petraea from the woodland centre

Average Age (years) Ilex aquifolium

Linear (Average Age (years) Ilex aquifolium )

Average Age (years) Betula Pendula

Linear (Average Age (years) Betula Pendula)

Distance from centre (DFC) (m)

Ave

rage

Tre

e A

ge (y

ears

)


The average age of Quercus petraea generally increases with DFC, but fluctuates at 75m and 125m DFC. Declines 50-75m DFC by 45 years to 112 years and 100-125m DFC by 65 years to 337 years are observed. Ilex aquifolium’s average age increases with DFC, but temporarily declines from 90 to 60 at 125m DFC.

DISCUSSION

Results

Patterns in the spatial distribution of tree species within Burton Bushes woodland reflect the historical management of Westwood pasture. The woodland inside the fence has not experienced grazing since 1980 and areas have reverted or are reverting into the closed-canopy climax community of deciduous woodland. Secondary autogenic succession is still occurring in this forest - although, due to the environments pressure induced from excessive grazing, sulviculture has been inhibited in some areas. The high abundance of juvenile trees within 75m DFC indicates a clear surge in regenerative capacity once the grazers were excluded from Burton Bushes. A higher abundance of juvenile trees [35> years] is located within 75m of the centre and the low abundance and species richness at 150m DFC indicates these areas were more impacted from the grazing than the intermediate areas. A theory for this vegetation transition gradient, may be due to excessive herbivore pressures causing tree species to primarily regenerating to the outer edges under low-lying shrubs offering protection (Vera, 2000). The successive areas deem conditions, physiology and vegetation composition of the subsequent successional stage - resulting in spatial variations in the growth stages – forming a structural diversity gradient across the woodland (Milchunas and Vandever, 2013). This in turn offers an explanation to how the taxon present became to be confined to its present spatial range.

4.1 Early Successional Stages

The younger trees within 75m DFC proved to be more susceptible to the environmental pressures inflicted by extensive grazing (Rotherham, 2013). They were inhibited from proceeding past the early-stage succession composition until ungulates were excluded, maintaining the juvenile woodland structure here.

4.1.1 Pioneer Stage (25m DFC)


This central area was dominated by Ilex-aquifolium; which autoecological study revealed was phytogeographically located due to it being the dominant pioneer species in Burton Bushes. Characterised by young trees [<63 years disregarding outliers, 11-110cm girth range – the largest a Crataegus pioneer species], a relatively low Quercus-petraea density (abundance 8) and high species richness and the greatest tree abundance. This phytosociological composition represents the early vegetation transition from the human-induced disturbance. Removing the human-induced control in Burton Bushes modified the competitive balance of the vegetation, promoting the invasion of extensive monoculture of pioneer species Ilex-aquifolium and small Crataegus abundance (Sutherland and Hill, 1995 and Walker and Moral, 2003). They have qualities enabling them to colonize poor conditions (Milchunas and Vandever, 2013). The low density of Quercus-petraea here - a light-dependent taxa - corresponds with the removal of the grazing ungulates (Vera, 2000) and subsequent colonization of Ilex-aquifolium species. They in turn facilitated autogenic succession. They have ideal qualities (Connel-Slatyer Facilitation Model of Ecological Succession (Bruno, Stachowicz and Bertness, 2003)) which improve conditions of the low-nutrient substrate, so the habitat was less hospitable for originating species’ ecological demands. Such colonising qualities include highly effective methods of dispersal and rapid growth rate (Walker and Moral, 2003). This facilitates the establishment of later-successional species (Quelch, 2001) which were native to this canopy before the disturbance on man according to Tweddle’s 2000 palynological study.

4.1.2 Overshoot Stage (50m DFC)

This area is characterised by high ephemerality and productivity (Wildlife Habitat Council, 2007) – and therefore the highest abundance and species. Which coincides with early-succession. A large tree age range was observed [120 years – excluding outliars] here, high tree abundance [50< trees] and spontaneous declines and fluxes in Ilex-aquifolium and Quercus-petraea respectively. This distinction in forest biomass in succession amplifies possible overshoot behaviour of the biomass (Shugart, 1998). The removal of the grazers enabled shade-tolerant opportunistic tree species exploit newly available fertile soil resources; there are no controlling parameters [i.e. predators and space (Milchunas and Vandever, 2013)] to limit population growth and resource consumption, and it continues with the excess nutrient availability (York and Schultz, 2011). This increase results in the habitats carrying capacity being exceeded by the ecological load, which must in time decrease and stabilize for establishment (York and Schultz, 2011), which is reflected as biomass reduces from this stage. The spontaneous Quercus-petraea and Ilex-aquifolium actions can be explained by the formation of a pre-climax community; new, favorable environmental conditions are created so Ilex-aquifolium is out-competed as it can no longer survive in the

Connel-Slatyer’s Facilitation model of ecological succession.

Ilex-aquifolium as a colonist species [A] tend to be good dispersers and grow fast, promoting colonisation of a larger ground area (Sutherland and Hill, 1995).

Source: Bruno, Stachowicz and Bertness, (2003).


new conditions (Shaw, 1968). Quercus-petraea is a light dependent tree, and the removal of the dense shrub-layer invites seedling germination (Shaw, 1968).

4.1.3 Transitional Stage (75m DFC)

This stage contrasts the characteristics of the overshoot stage; characterised by a spontaneous increase and decline in Ilex-aquifolium and Quercus-petraea respectively and a smaller age range [202 years]. Anomalous observations in the physiognomy of Ilex-aquifolium and Quercus-petraea species were observed. These observations may represent ‘temporary shifts’ in species composition, representing the cohort-re-establishment phase (Franklin et al¸ 2002) from early to mature-successional woodland (Wildlife Habitat Council, 2007). The overshoot stage demonstrated highly ephemeral growth beyond sustainable environmental limits. This stage represents the recovery period after the ‘crash’ of that species composition (York and Schultz, 2011) and transition into a more sustainable species structure with smaller tree abundance. The re-emergence of Ilex-aquifolium indicates a repeat of the pioneer stage, although a distinction from the original pioneer stage is the ecological stability demonstrated by high tree richness. An offered explanation is the early occupants modifying the environment so it becomes less suitable for subsequent recruitment species, but more suitable for recruitment of the mature-successional species (Connel and Slatyer, 1977). Over ecological time, several transitions in species composition may occur in an area, coinciding with changing environmental conditions re-determining geographical ranges of species (Cox and Moore, 2005).

4.2 Late-successional stage

The mature trees within intermediate woodland areas proved to be less susceptible to the environmental pressures inflicted by extensive grazing; evident by their stabilising tree age ranges, and maintained high species richness at low numbers. The ecosystem experiences slow but systematic modifications as the community assembly proceeds.

4.2.1 Climax Community (100-125m DFC)

The stable, but dynamic state of Burton Bushes contains a balanced equilibrium of established native species (Tweddle, 2000), This climax stage is characterized by a stabilisation in age distributions [range of 398 years], higher densities of mature trees, stabilised low abundance of trees indicating slower productivity, significantly higher and lower densities of Quercus-petraea and Ilex-aquifolium respectively. A healthy wood pasture should possess a range of different ages (Quelch, 2001); largely due to the pressures from grazing and the resultant structural diversity gradient, Burton Bushes has a recovering diverse tree age matrix. Therefore explaining the higher density of mature trees here.

Quercus-petraea the foundation species of Burton Bushes, which resisted grazing pressure (Ellision et al, 2005; kind of keystone species, but with a focus structure), exists throughout the woodland dominantly in areas favourable to its geographical and phytosociological range (Vera, 2000). Ilex-aquifolium density declines subsequently by being outcompeted once an area has been heavily populated by surrounding species (Milchunas and Vandever, 2013) and populations diminish (Vera, 2000). This is considered a sign of a successfully regenerating population. (Malmer et al. 1978, Emborg et al. 1996).

4.3 Retrogressive succession and grassland


Human-induced environmental controls have created simplistic phytosociological composition, allogenic in nature. Quercus-petraea remain unsusceptible to the environmental pressures and remain in clusters varying in age due to the absence of the dense canopy and ability of seedlings to establish in open grassland (Vera, 2000).

4.3.1 Parkland (150m DFC)

This area is characterised by sparsely populated ancient [11-398cm girth range] Quercus climax trees in a park-land landscape, representing a deflected community of grassland (Milchunas and Vandever, 2013). The historical human-induced pressure of grazing reduced the regenerative capacity of the native trees and shrubs, resulting in retrogressive succession (Gleason, 1926 and (Ellenberg, 1988). Simplification here is evident by only sessile-oak being present (Pigott, 1983). The trees have a high age range [38< years], with a relatively high density of juvenile trees representing the regeneration since the exclusion of large ungulates. Different environmental controls are exerted on this land from recreational use, therefore present abiotic pressures are preventing further succession.

4.3.2 Outside fence (175m)

This area constitutes of grassland with very low abundance [<4] of the largest girth Quercus-petraea trees. Human-induced pressures from recreational activities control the environment, inhibiting succession. The Quercus-petraea which exist here resisted the pressure from the grazing.

4.3 Broad Perspective

Disturbances act on different spatial and temporal scales; each forest thus constitutes a unique combination of abiotic and biotic factors. The interlinked association between succession and disturbances and anthropogenic impacts on forests, permanently reorganise forest structure and species diversity (Fischer, Marshall and Camp, 2013). To demonstrate, a meta-analysis of European forests (Paillet et al, 2009) discovered species richness was greater in unmanaged forests.

This has imperative consequences for forest management in temperate forests. Methods of timber production and harvesting that use single-tree or group selection methods are partial to patchy harvesting units, and which mainly use natural generation of tree species to transition to the natural functioning of temperate deciduous forests than uniform methods (Fischer, Marshall and Camp, 2013). Fischer demonstrated such selective cutting practices may mimic natural forest disturbances, increasing species diversity (vascular plants and soil fungi). In hindsight, managed forests disturbances should not only be seen as a production obstacle but as a chance to incorporate natural ecosystem processes into production systems (Vera, 2000). Spatial variation in disturbance can be seen as beneficial for forest regeneration. In Denmark, regulated selective cutting systems have been using as standard sulvicultural method since the 18th century (Ellenberg, 1988). Studies have implied that management impacts on forest ecosystems after a disturbance often impose greater environmental impacts on forest ecosystem, and conclude that doing nothing is a viable alternative’ site specifically methods (Fischer, Marshall and Camp, 2013).


Governments and policy makers should put creating an environment to foster adaptation in forestry at the forefront of their decision making. Finally climate change is superimposing itself on forest development worldwide. Future climate change will affect society's ability to use forest resources and intensify declining global biodiversity. Approximately 50% of all terrestrial plant species are living on only 2.3 % of the land area – which is predominantly dominated by forest ecosystems (Seligmann et al. 2007). Forestry management is not only responsible for sustaining a natural resource and regulator, but sustainably protecting natural biodiversity.

Limitations

The sample size was insufficient; only a small proportion of the entire woodland has been interpreted. Point estimation was the method used to collect the samples, from which the entire woodland’s tree spatial distribution and associations was estimated. The whole woodland was not represented by the data, the collected data could have been anomalous. Additionally, some areas of the woodland were deemed unsafe or inaccessible, such as the centre. This reduced the reliability and accuracy of the final outcome as it is an estimation.

Methodological error may have occurred, such as false identification of tree species. A species-area curve was not drawn in the field to determine the optimal quadrat size to sample adequately the degree of variation; the predominant use of 10m² quadrats [due to limited time] may have reduced the validity of the results. Collecting data on ecological and climatological parameters – such as wind or soil – could have allowed further investigation and provide greater evidence.

CONCLUSION

The environmental controls exerted from previous disturbance and management on Burton Bushes are strongly reflected by current composition and spatial distribution of tree species. A structural diversity gradients exists through the wood due to the disparity in growth phases as a result of a successional gradient – which all result from the impacts and varying levels of inhibition of historical grazing on the Westwood pasture. It is vital sustainable forest management approaches are integrated globally so use can be continued without abuse.


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APPENDICES

Appendix A:

Figure 1 Geographical location of the Kakamega Forest (red square) and Satellite image (Landsat 7 ETM+, 05 Feb 2001) of Kakamega Forest and its fragments.

Demonstration of severe environmental consequences from human-induced environmental pressures; fragmentation of the ancient Guineo-Congolian rainforest.

Source: Source: village-sanctuary.com and BIOTA-E02, G, Schaab, in Yeshitela, 2008.


Appendix B

Raw data.

Distance from centre Transect Species Tree age (years) Girth (cm) Height (m)

25 a Holly 31 11 2

25 a Holly 31 11 2

25 a Holly 34 17 2

25 a Holly 37 24 3

25 a Holly 38 25 3

25 a Holly 42 30 5

25 a Holly 42 30 3

25 a Holly 46 35 4

25 a Holly 47 36 3

25 a Holly 47 36 5

25 a Holly 50 39 4

25 a Holly 54 43 5

25 a Holly 56 45 4

25 a Holly 59 47 6

25 a Holly 60 48 6

25 a Holly 61 49 7

25 a Holly 61 49 5

25 a Holly 65 52 4

25 a Holly 67 53 5

25 a Holly 69 55 4

25 a Holly 80 62 8

25 a Holly 94 70 8

25 a Holly 94 70 9

25 a Oak 104 49 5

25 a Hawthorn 11 26 2


25 a Holly 32 14 1

25 a Holly 36 22 3

25 a Holly 37 24 3

25 a Holly 39 26 2

25 a Holly 42 30 5

25 a Holly 58 46 6

25 a Holly 63 50 4

25 b Hawthorn 3 10 2

25 b Hawthorn 165 110 18

25 b Holly 48 37 4

25 b Holly 63 50 7

25 b Holly 82 63 10

25 b Holly 94 70 8

25 b Holly 158 99 11

25 b Oak 38 10 1

25 b Oak 38 10 1

25 b Oak 46 20 2

25 b Oak 68 34 3

25 b Oak 72 36 4

25 b Oak 81 40 3

25 b Oak 176 70 5

25 b Beech 117 70 20

25 b Holly 31 11 1

25 b Holly 32 14 1

25 b Holly 35 20 3

25 b Holly 39 27 3

25 b Holly 69 55 5

25 b Holly 112 79 9

25 b Holly 151 96 14

25 b Silver birch 15 72 10





50 a Ash 103 62 11

50 a Beech 63 17 3

50 a Beech 68 26 4

50 a Holly 31 11 2

50 a Holly 36 22 3

50 a Holly 36 22 3

50 a Holly 37 23 3

50 a Holly 41 29 4

50 a Holly 51 40 5

50 a Holly 51 40 6


50 a Holly 56 45 5

50 a Holly 58 46 3

50 a Holly 61 49 5

50 a Holly 69 55 5

50 a Holly 77 60 7

50 a Ash 120 71 10

50 a Holly 34 17 2

50 a Holly 34 18 3

50 a Holly 45 34 5

50 a Holly 77 60 9

50 a Silver birch 39 34 4


50 b Ash 78 45 6

50 b Holly 46 35 3

50 b Holly 56 45 3

50 b Holly 102 74 7

50 b Oak 38 10 1

50 b Oak 41 15 1

50 b Oak 42 16 2

50 b Oak 42 16 2

50 b Oak 47 21 2

50 b Oak 49 22 2

50 b Oak 85 42 4

50 b Oak 138 60 5

50 b Oak 176 70 6

50 b Oak 184 72 5

50 b Oak 268 90 11

50 b Oak 370 108 10

50 b Oak 456 202 20

50 b Holly 36 22 3

50 b Holly 48 37 3

50 b Holly 60 48 7

50 b Holly 63 50 6









75 a Holly 33 16 2

75 a Holly 36 21 3

75 a Holly 51 40 5


75 a Holly 58 46 4

75 a Holly 64 51 6

75 a Holly 69 55 7

75 a Holly 84 64 5

75 a Holly 94 70 7

75 a Holly 131 88 8

75 a Holly 189 110 14

75 a Holly 418 172 16

75 a Oak 121 152 16

75 a Ash 60 140 20

75 a Hawthorn 3 10 1

75 a Holly 31 9 1

75 a Holly 38 25 4








75 b Ash 63 31 6

75 b Holly 39 26 3

75 b Holly 42 31 3

75 b Holly 54 43 4

75 b Holly 84 64 7

75 b Holly 110 78 9

75 b Holly 112 79 9

75 b Holly 161 100 11

75 b Oak 180 71 7



75 b Ash 52 110 16

75 b Ash 70 140 18

75 b Ash 184 98 17

75 b Beech 151 210 25

75 b Holly 30 7 1

75 b Holly 31 8 1

75 b Holly 31 11 1

75 b Holly 39 26 4

75 b Holly 39 27 3

75 b Holly 42 30 5

75 b Holly 58 46 4

75 b Holly 60 48 5

75 b Holly 65 52 8


75 b Holly 67 53 5

75 b Holly 100 73 8


100 a Holly 45 34 5

100 a Holly 50 39 5

100 a Holly 69 55 6

100 a Holly 89 67 7

100 a Holly 94 70 8

100 a Holly 114 80 9

100 a Holly 302 144 18

100 a Holly 59 47 5

100 a Holly 84 64 9






100 b Ash 148 84 11

100 b Ash 176 130 17

100 b Beech 172 235 25

100 b Holly 94 70 8

100 b Holly 108 77 8

100 b Holly 219 120 14

100 b Oak 400 157 14




100 b Ash 120 71 9

100 b Ash 497 179 25

100 b Holly 30 6 1

100 b Holly 32 12 1

100 b Holly 41 29 3

100 b Holly 47 36 4

100 b Holly 61 49 7

100 b Holly 69 55 6

100 b Holly 72 57 6

125 a Holly 41 29 4

125 a Holly 45 34 3

125 a Holly 49 38 5

125 a Holly 52 41 5

125 a Holly 72 57 5

125 a Holly 122 84 8

125 a Holly 143 93 12

125 a Oak 412 270 25



125 a Ash 65 33 4

125 a Ash 78 45 6

125 a Ash 135 78 10

125 a Ash 155 111 18

125 a Oak 72 36 3

125 a Oak 119 54 5

125 a Oak 184 72 7

125 a Oak 214 79 9

125 a Oak 247 86 8



125 b Ash 118 70 9

125 b Ash 148 84 14

125 b Ash 173 94 11

125 b Beech 72 32 5

125 b Beech 81 43 3

125 b Beech 90 51 5

125 b Beech 99 58 4

125 b Oak 160 66 6

125 b Oak 223 81 8

125 b Oak 39 12 1

125 b Oak 43 17 1

125 b Oak 45 19 2

125 b Oak 46 20 3

125 b Oak 47 21 2

125 b Oak 53 25 2

125 b Oak 64 32 3

125 b Oak 68 34 4

125 b Oak 85 42 3

150 a Holly 77 60 7

150 a Holly 134 89 8

150 a Holly 136 90 10

150 a Holly 177 106 12

150 a Holly 206 116 11

150 a Oak 213 259 25

150 a Oak 56 27 3

150 a Oak 70 35 4

150 a Oak 96 46 4

150 a Oak 98 47 4

150 a Oak 184 72 7

150 a Oak 352 105 10

150 a Oak 356 340 30

150 b Oak 223 320 25


150 b Oak 423 160 15

150 b Oak 38 11 1

150 b Oak 50 23 2

150 b Oak 88 43 4

150 b Oak 153 64 5

150 b Oak 220 390 30

150 b Oak 321 272 25

150 b Oak 366 370 30

final biog

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