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  • Date:2012-06-11

Experimental forests are the outdoor laboratories of the forestry industry. They are venues for testing both scientific hypotheses and forest management regimes, and also play a valuable role in forestry education. It is therefore important to use the most modern methods in the planting and management of experimental forests, and to maintain a focus on the changing needs of the forestry industry. Experimental forests must provide varied environments and materials for long-term and short-term experiments. They are necessarily local in their nature, so they must work with local industry and take advantage of local conditions.

In modern forestry, the foundational concept is forest ecosystem management. The forest ecosystems are a key part of the biosphere, and one of the most important resources for human beings. The management of this precious resource is therefore the key task for foresters. Ecosystem management is a very broad area for research, but three aspects are considered to be most important: monitoring changes in the global environment, preserving biodiversity, and cultivating sustainable ecosystems. Other issues of pressing relevance in ecosystem management include: species and habitat diversity; ecosystem distribution and link-ups; ecosystem energy production and storage; ecosystem complexity and its importance for sustaining life on earth; the role of biodiversity in ecosystem control; maintenance and restoration of biodiversity through ecosystem processes; planning for managing sustainability and ecosystem restoration. These are the primary issues faced in Taiwanese forestry.

Forests are in principle a renewable resource. Forest management involves understanding the cycles of forest growth and regrowth, and acting to maintain, improve or restore forest productivity. This principle of renewability informs the entire practice of forestry: choice of tree species; cultivation of saplings; afforestation methods and design; tree cultivation practices. The goal of all forestry practice is sustainability of the forest resource and forest productivity. Forestry is also a primary industry, so maintaining and improving productivity over the long term is the decisive factor in sustainable management. In long term planning for sustainable development in the forestry industry, it is necessary to use ecosystem management concepts. The basis of all forestry must be the forest as ecosystem.

Experimental forest operations

In the past, forestry involved cutting down large swathes of old growth hardwood forest, and replanting with a monoculture of a single commercial species. However, that model has changed. It is now illegal to log old growth forests, and there are explicit guidelines in the Forest Law and the Plan for Operation of State-owned Forest Industry Zones. Modern forestry involves improving low-grade forest, reforestation with hardwood species, maintenance of new forests. The focus is on conservation of resources and ecosystems, and maintaining or improving productivity.

Improving low-grade forest

Many of the planted forests in Taiwan have only a single species of tree, all of the same age. They are often planted on areas of natural forest that have been cut down, to restore forest cover. Trees were often selected because they were commercially profitable, easy to cultivate, grew fast, and could be logged quickly. Ecologically speaking, these planted forests are very different from the natural forest they replaced, both in terms of the species represented and their ecological structures. Despite the differences, this approach has been successful in many cases. However in some areas environmental conditions have adversely affected the planted forest. Reductions in the complexity and diversity of the forest ecosystem have lowered the forest's resilience to external shocks. For example, red-bellied tree squirrels have caused great damage to plantations of cryptomeria (Japanese cedar) and Cunninghamia (China-fir).

There are nearly 100,000 hectares of planted forest in Taiwan, and many areas have suffered damage. In order to improve the quality of these areas, intensive cultivation techniques can be combined with insights from restoration ecology. Young trees can be added, either through natural seeding or by taking grafts. Hardwood species native to the area can also be interplanted. The plantation should slowly turn into a half-natural forest. Where conditions are adverse, and many trees are dying, second-phase reforestation can be considered. First, fast-growing species which can suppress weeds are planted to complete the forest canopy. Hardwood species can then be interplanted, to ensure some return on the costs of forest management.

Afforestation with native hardwood species

Hardwood cultivation is an important area of forestry research. Planting hardwood forests brings the benefits of restoring Taiwan's original environment and preserving biodiversity, but in early afforestation projects in Taiwan, native hardwood species were often ignored. Both economic and political factors contributed to this omission, but the most important cause was problems with the cultivation technology available. Forestry workers were unwilling to use many hardwood species, because of the difficulty associated with their cultivation. Hardwood seeds are difficult to store and germinate; early growth is slow; survival rates are low; stems tend to split.

However, solutions to most of these problems have been found in recent years. For example, cold stratification can solve problems of storing and germinating recalcitrant seeds; dibble tubes can ensure good root development, and reduce the need for top-pruning or root-pruning when transplanting; intensive nursery management techniques such as automatic sprinklers and fertilization systems have brought great improvements in survival rates and stem splitting. With these advances, hardwood afforestation is now basically viable. This laboratory has performed pioneering experiments in seed storage, germination, dibble tube cultivation, fertilization, etc, and is now producing viable saplings in sufficient numbers to supply hardwood afforestation projects. Experimental forestation zones have been set up, and hardwood saplings transplanted. It is hoped that data on the saplings' adaptation to their environment will serve as a basis for future planting of mixed and multi-storied forests and for the cultivation of hardwood forests after transplantation.

Forest cultivation and maintenance

Taiwan has planted forests of all ages, and at every stage of growth. In order to raise a forest of the highest quality, different forestry techniques must be employed throughout the life cyle of the forest. A forest which has developed well can be thinned and pruned in order to obtain prime, unknotted timber. A forest whose development has not been so successful can be interplanted to fill in gaps in its ecosystem. Another solution for problem forests is to assist the development of a stable and robust ecosystem by intensive care for hardwood seeds and saplings. Most importantly, diversity of species and ecological balance must be maintained.

There are many considerations when planting a forest. These include: natural replenishment of both conifers and hardwoods; protection and management of old growth forest; selection of a permanent site; full survey of the area; creating a forest stand which will be attractive; conservation issues and forest maintenance; and how forest industries will fit into the overall ecosystem. The landscape ecology of a new forest is to be taken into deep consideration. The overall aim is to protect natural resources at the same time as ensuring high productivity. When the project is an experimental forest, effective management also enables botanical research to be completed more efficiently.

Experimental forests have a number of other functions: they enable effective botanical research; enable research results to be made widely available; assist in the development of forestry practices; improve botanical education and the availability of botanical information; promote links between botanical research organizations on a national and international level. Managers of experimental forests must play an active role in analyzing, publicizing and explaining their research.

In conclusion, the principal aims of experimental forests are as follows:

  • To play a leading role in the protection and development of natural resources
  • To be a research site for maintaining and improving forest productivity over the long term
  • To provide botanical education and promote research into forest management techniques