Estimating Potential Productivity of Forests

This Chapter describes approaches for estimating growth and yield of tropical forests based on climatic data, which are available now for most of countries in form of a time series, a subject of very high interest for the tropics in the light of most of s

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Estimating Potential Productivity of Forests

14.1 The Need for Potential Productivity Estimation In 1956, a Swedish geographer S. S. Paterson published a paper with the title: ‘‘The Forest Area of the World and its Potential Productivity’’. In this paper, the author presented an index to derive forest potential productivity for all climatic regions of the world from only a small amount of easily obtainable climatic parameters. The FAO Forestry Department was obviously very interested in the paper and requested the International Union of Forest Research Organizations (IUFRO) to check the validity of Paterson’s index. In November 1958, a working group was formed including eight scientists from the main climatic regions of the world under the chairmanship of Prof. J. Weck of Germany. Since time was rather short (to the 1961 IUFRO Congress in Vienna), the working party could check the validity of the index only in those regions, where climatic and forest productivity data were already available (Weck 1961, 1962). Members of the working party soon came to the conclusion that an index based on climatic data alone cannot completely explain the quality class of specific forest sites, because the site quality does not depend on climatic influences alone, but also on the characteristics of the soil and the genetic make-up of species growing at the site. Still, it was of great interest (with special reference to tropical regions) to determine, whether an index based on climatic data alone could be developed for estimating average potential productivity of forests in regions with a certain climatic uniformity and normal distribution of soil quality classes. Obviously, this assumption could be tested statistically only in the temperate and boreal zones, on account of non-availability of climatic and forest productivity data in the tropics. Weck (1955) had already carried out studies for the forest regions of Germany on climate and forest productivity relation and found good correlation coefficient of 0.83 between mean values of sustained yield of forest and the corresponding values of a climatic index proposed by him. Altering the index value by 100 units

K. D. Singh, Capacity Building for the Planning, Assessment, and Systematic Observations of Forests, Environmental Science and Engineering, DOI: 10.1007/978-3-642-32292-1_14,  Springer-Verlag Berlin Heidelberg 2013

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Estimating Potential Productivity of Forests

altered mean annual yield of the forest area by 0.69 ± 0.14 m3 per year and hectare. The unanimous view of the working party submitted to FAO was as follows: • In general, the quality class of individual forest sites cannot be determined accurately enough solely from a climatic index. • For restricted regions there are indications that it may be possible to find empirical functions, based on physiological principles, which permit sufficiently accurate correlation between climatic index and the mean potential production of forest areas within those regions. The situation regarding availability of climat

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