Bangor Diverse

Title of Experiment: Bangor DIVERSE

Date planted: March 2004

Contact: Dr Andy Smith

Funding sources: Science Research Investment Fund (SRIF),
Forestry Commission, Centre for Integrated Research in the Rural Environment (CIRRE).

Location: Henfaes Experimental Lowland Station

Websites http://www.treedivnet.ugent.be/SiteBangor.html
http://diverse.bangor.ac.uk

Data repository: U:\College of Natural Sciences\SENRGy\BangorDIVERSE

Background


Forests provide many ecosystem services to humankind that include, but are not limited to, flood defences, carbon sequestration and the provision of fresh water.  Historically, and for logistical reasons, much of the research investigating species diversity, ecosystem functioning and productivity has been conducted in the laboratory or grassland field trials.  Recent research has shown that species rich ecosystems have a decreased mean of many ecological process rates, yet can also be more productive and interact with global change drivers.


Ecological theory suggests that high diversity should provide greater resilience and stability to the provision of ecosystem services whilst under the influence of global change. Recent data has shown species diversity loss to be a major driver of global ecosystem change highlighting an urgent need for research into forest diversity and ecosystem function.

Experimental Aims

  • Determine how tree species diversity impacts forest productivity and ecosystem function.
  • Examine and quantify the effects of altered species richness and functional diversity on key ecosystem processes including C sequestration.
  • Elucidate the mechanisms underpinning diversity - function relationships.
  • Describe how species diversity alters pest susceptibility, transmission and forest stand resilience.

Figure 1. Location of the BangorDIVERSE 2.36 ha plantation; the two fields contain 92 plots in four replicated blocks of one, two and three species mixtures planted at a density of 10,000 stems ha-1  in 2004 and thinned to 2500 stems ha-1 in 2013

 


Figure 2. Position of the 92 individual species plots across the two fields that comprise the experiment

 

Description


BangorDIVERSE is a forest diversity experimental infrastructure at Bangor Universities' Henfaes Research Centre (Figure 1), which aims to explore the relationship between tree diversity and forest ecological functioning and sustainability. The experiment, established in March 2004, is comprised of 92 plots (Figure 2) in a fully replicated (n=4) planting design of one, two and three species mixtures of alder (Alnus glutinosa L.), birch (Betula pendula Roth), beech (Fagus sylvatica L.), ash (Fraxinus excelsior L.), sycamore (Acer pseudoplatanus L.), chestnut (Castanea sativa Mill.), and oak (Quercus robur L.) at a density of 10,000 stems ha-1. The species were selected because of their contrasting shade tolerance, successional chronology and to represent a range of taxonomic, physiological and ecological types.

Site characteristics

Area

2.36 ha

Number of plots

92

Number of trees planted

22,000

Planting date

March 2004

Former land use

Both fields were originally pastures. One field has been used for small-scale forestry experiments for the last 20 years; the other field was ploughed and planted with oilseed rape in 2003.

Altitude

13-18 m

Soil type

Fine loamy brown earth over gravel (Rheidol series), classified as Fluventic Dystrochrept.

Species pool

Alnus glutinosa, Betula pendula, Fagus sylvatica, Fraxinus excelsior, Acer pseudoplatanus, Castanea sativa, Quercus robur

In 2013 BangorDIVERSE joined the International Tree Diversity Network (Figure 3) improving the possibilities for international collaboration and experimental replication throughout the network.

Figure 3. BangorDIVERSE is part of the international tree diversity network (TreeDivNet) of 16 forest diversity experiments world wide

Planting Design

Plots were established across the two fields in four replicated blocks of single, two and three species mixtures. A replacement series design (with inter-tree spacing constant between treatments) was selected because of the experiment's objective of being realistic in reflecting the practical realities of how forests comprising monocultures or mixtures of potential canopy tree species could be established. The site was planted with 60 cm saplings of each species with an inter-tree spacing of 1 m (10,000 stems ha-1). A systematic hexagonal planting design (Figure 4), i.e., each tree having six equidistant neighbours, was used to maximise the mixing effect. In the three species mixture blocks, the nearest neighbours of each tree were two conspecific individuals and two individuals of each of the other two species.


Figure 4. Hexagonal planting design

 

 

Site maintenance


In 2004, the site was ploughed in preparation for planting. The perimeter of the entire plantation was fenced to protect the saplings from rabbits. Trees were watered during the first few months following planting to reduce transplant mortality. During the dormant winter period of 2012-13 the plots were thinned to 2,500 stems ha-1. No other management interventions have taken place.


Publications arising from this experiment

Ahmed, I.U.M.T, Smith, A.R., Jones, D.L., Godbold, D.L. (in prep) Tree
species identity influences the accumulation of recalcitrant deep soil carbon.
Ahmed, I.U.M.T. (2011) Ecosystem carbon dynamics: as influenced by
tree species and mixture in a temperate deciduous woodland. PhD thesis, Bangor University, Bangor, UK.

 

Photographs of the experiment

 

Plate 1. Forestry technician Mike Bambrick removing a single ash (Fraxinus excelsior) sapling during the thinning operation of 2012-2013

 


Plate 2. Three species mixture plot before thinning.

 


Plate 3. Sprouting of Acer pseudoplatanus from the stump of a felled tree.

Plate 4. View of the Aber valley from across the top of the BangorDIVERSE plantation.


Plate 5 Dryopterris affinis growing amongst Betula pendula and Quercus robur. two species plots