A compatible system for estimation of individual tree volume was developed for Scots pine (Pinus sylvestris L.) in northwestern Spain. The system comprises a merchantable volume equation, a total volume equation, and a taper function. The use of the volume equation allows rapid estimation of tree volume, and stand volume by summing individual tree volumes, which is equal to the volume obtained by integrating the taper equation. The volume equation is very easy to use and is therefore preferred when classification of the products by merchantable sizes is not required. Data from 228 destructively sampled trees were used for model development. Fourteen compatible volume equations were evaluated, 13 of these equations were taken from the available literature, and the other was developed in the present study. A modified second-order continuous autoregressive error structure was used to correct the autocorrelation of the hierarchical data used. The model developed by Fang et al. (Z. Fang, B.E. Borders, and R.L. Bailey. 2000. For. Sci. 46: 1–12) best described the data. There model is therefore recommended for the estimation of diameter at a specific height, merchantable volume, and total volume of Scots pine stems in the area of study.

A stand density management diagram (SDMD) was constructed for Pinus radiata D. Don plantations in Galicia (north-western Spain) on the basis of four equations that were fitted simultaneously to data collected from 223 permanent plots. The relative spacing index was used to characterize the growing stock. The diagram provides information about quadratic mean diameter, stand merchantable volume, stand above-ground biomass, stand stem biomass and stand carbon pools. In addition, an estimation of the average slenderness coefficient for the whole stand and for each quarter of the stand diameter distribution was included. This information can be used to assess the stability of the whole stand and different crown classes, respectively. The SDMD outlined here allows foresters to make quick and easy comparisons among different thinning schedules in which both timber production and the risk of damage from wind or snow are considered. Two alternative density management systems, one that includes thinning operations and another that only includes the density-related mortality provided by a mortality function, are outlined in the diagram.

Annals of Forest Science, is a source of information about current developments and trends in forest research and forestry