| Тойм: | <p>This manual provides a reference guide to permanent sample plot (PSP) techniques in mixed tropical forests. It is intended as an update to Synnott's <em>Manual of permanent plot procedures for tropical rainforests.<em> The manual considers the objectives of PSPs as that of providing data for growth and yield models which will be used to assist forest management. The PSPs are a means of measuring tree growth, mortality, and regeneration in relation to stand density. They may be laid down either as a network of sampling plots, passively sampling existing forest management practices; or as measurement plots within an experimental design. Both approaches are properly required for the optimum capture of data. There is no satisfactory method of calculating numbers of PSPs required, but approximate indications are that one plot per 1000 ha of forest, laid in a stratified random sample, will normally be adequate. Experimental designs should concentrate on the effects of extremes of stand density, from controlled logging or poisoning, and always include untreated and unlogged forest as a control to define maximum basal area and growth under maximal competition. Randomized block design is recommended as simple, robust and statistically rigorous. Replicates should be placed on different sites.</em></em></p> <p>When considering plot shape and size, some compatibility is required with temporary plots used in forest inventory. Measures of basal area, competition and spatially-dependent ratio parameters will depend on plot size and shape, hence the need for some consistency. In general, a square PSP of 100 x 100 m, subdivided into 25 20 x 20 m quadrats, is recommended, but this may be varied where compatibility requirements so indicate. Compatibility can be achieved for various shapes and sizes by using a common sub-unit. For this purpose the 20 x 20 m quadrat is recommended as a basis for all permanent, temporary, and experimental plots. For plot location in the field, modern methods using global positioning satellites may greatly reduce survey time and cost, and ease the problem of relocating plots in future. Plots can be permanently demarcated by use of a combination of concrete or hardwood corner pillars, trenches to relocate boundaries, and use of tree numbers and positions to reconstruct the plot should corner markers be lost.</p> <p>On plots, trees above 20 cm dbh should be permanently marked with paint or tags, uniquely numbered, and measured for diameter, crown position and crown form according to the Dawkins classification. Qualitative records of damage, disease or other features should be made via coded notes. A sub-sample of two trees on each plot should be measured for crown point height. Trees below 20 cm should be measured on a subplot, and if possible regeneration on an inner subplot or sample strip. All species should be measured, without consideration of economic utility. The manual covers site assessment briefly, including topographic indicators based on altitude, slope and aspect, soil sampling and classification methods, the use of vegetation associations as site indicators, and the use of quantitative stand parameters such as mean height and form height. Data recording forms are given, together with a description of database record structures compatible with the forms, and methods for data entry verification and the management of long-term data storage.</p>
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