Forest Dynamics

Trees are the dominant and distinguishing life form of forests; they create the structures that make forests unique. Not surprisingly then, the knowledge gained from studying trees is fundamental to ecological forest management. This knowledge must be understood and applied at larger spatial scales, however, because mana ging individual trees is not practical. This need forges a link with community and landscape ecology, which study the patterns and processes of forest growth and the inter active effects of competition, succession, and disturbance dynamics.

Case Study 1 Loch Lomond and the Trossachs National Park, Scotland

Scotland's first national park was officially opened by Princess Anne in July 2002. The Loch Lomond and the Trossachs National Park encompasses around 1865 km2 of some of the finest scenery in Scotland. More than 70% of Scotland's population lives less than an hour's travel time from the park. It is estimated that 3.2 million people visit the park every year, and 15 600 live within the park boundary, so managing the forested landscape for aesthetic views (see Figure 1) and recreation is a priority.

Figure 1 Scottish landscape showing diversity of vegetation patterns.

Within the park, the Cowal and Trossachs Forest District occupies an area of 66 000 ha. This part of west central Scotland has a predominately temperate climate, receiving annual rates of precipitation of between 3600 mm in the west and 1520 mm in the east, with mean annual temperatures of 8.5 °C. Most of the natural oak woodland vegetation has been replaced with plantations of commercially managed conifer forests, which contain both native (i.e., Pinus sylvestris) and non native tree species (e.g., Picea sitchensis, Pseudotsuga menziesii, Larix decidua). Most plantations were established between 1942 and 1971, following a time of intense forest depletion from the late 1800s through World War I.

Within the Cowal and Trossachs Forest District, the Achray forest is dominated by European larch (Larix deciduas). Most were planted around 1939. It has been managed by using a low thinning management regime typically practiced from age 20 years onward. This involves removing 70% of the tree maximum annual increment at 5 7 year intervals. Timber production is the main management objective for these stands, but since they lie within the park landscape, visual maintenance and the quality of visitor experience are also important. The Achray forest is visited by 140 000 visitors per year, according to the David Marshal Lodge visitor center. This stimulated a move away from the traditional silvicultural system of clearcutting stands at optimum age, toward a system that will maintain a continuous cover of trees in the landscape. Managers are now trying to use systems that mimic ecological forest processes of stand disturbance and natural recruitment of seedlings.

Forest soils in the area are nutrient rich, well drained upland brown earths, which support vegetation rich swards where light levels permit. This sward develops beneath the larch stands and then becomes one of the main barriers to natural recruitment of seedlings. Slopes are relatively steep and preclude the use of machinery for harvesting and extraction; manually felling with chain saws and cable crane extraction are the preferred operation. All management operations conform to the United Kingdom Woodland Assurance Scheme (UKWAS) standard and are Forest Stewardship Council (FSC) certified (see Case study 3 for details on the FSC).

Most large dimension timber goes to local sawmills within an 80.47 km radius of the forest. Smaller material is used for pallet production and is taken to a medium density fiberboard mill within 40.23 km. Local markets place a financial penalty on noncertified timber.

By Colin Edwards

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