Site factors and variables that best explain productivity variability were determined for sites with adult Pinus radiata plantations. The study covered 70 sites in Central Chile (33°-41° S) with great climate and soil variations. Through correlation analysis, step-wise and linear regression, climate stood out as the main factor of productivity variability. According to this result, the need to analyze sites with sandy soils separately from those with non-sandy soils became evident. The water regime, through the soil physical and climatic variables, was shown have the greatest effect upon productivity; the regime of soil nutrients was shown to have a lesser effect.

The prospects of plantation forestry are good. They are strengthened by several inter-related developments includ­ ing the expanding role of plantations in meeting the global needs for wood, urgent concerns about the loss of native forests, the potential value of plantations as an integral part of land and environmental care, and the contribution of plantation forestry to economic growth in many countries. Furthermore, timber has many advantages as a construction material over other products including steel, aluminium and bricks, in terms of desirable criteria for low energy requirements and carbon emissions. Chilean forestry has been in the forefront in recognising the need and opportunity of plantation forestry and has developed a large resource base within a relatively short time. This achievement has been based on exotic species, mainly Pinus radiata and Eucalyptus globulus. These species have many attributes in terms of growth potential, responsiveness to management practices and wood properties. P. radiata wood exceptionally versatile and suitable for a variety of end products and E. globulus is recognised as a premium quality pulpwood. Plantation forests in southern Australia are also based on these species and it appears that the land base in Australia and Chile have several environmental factors in common. What can we then learn from our combined experience?

The excellent quality of Lenga wood makes it usable for a large number of purposes. However, sawmills located in Chubut Province, Argentina use it to mostly produce construction timber since most of Lenga logs have high percentages of a wood-rot due to sanitary problems. The objective of this study was to find a way to produce higher quality products from low quality logs. This study evaluated the feasibility of setting up a Lenga solid-board factory. To run the study 14 m3 of sawlogs were sawn and all timber pieces produced were measured. The results show that it is possible to improve the use of sawn Lenga timber.

N. desantisi was found, for the first time, as a new species in the lower valley of Rio Chubut, Argentina, in 1980/ 81. It showed an extensive and fast spread in this country (3.000 km in 9-10 years). It was detected in Santiago de Chile in 1983/84. It causes intensive defoliations and loss of trees in Salix sp., and it also damages Populus sp., very important trees in Patagonia. Consequently it was decided to study its bioecology in Rio Negro and Neuquen. The results indicate that, at present, it is found in the whole basin of the rio Negro. The following aspects are described: date of beginning the oviposition, date of starting in diapause, oviposition and morphology of egg, larvae, pupae and imago. It has 4-5 generations/year, and these are overlapped. Three new parasitoids were found which were classified by De Santis: Pteromalidae sp., Isdromas gigantii sp. nov. (Ichneumonidae) and Cirrospilus gracielae sp. nov. (Eulophidae). The following species are mentioned as new hosts: Salix alba, S. elegantissima, S. matsudana and Populus alba.

I Región, Chile)

SUMMARY The technical feasibility and the effect of a hydrophobic substance on particleboards made with the logging residues of Olivillo, and Pino insigne wood was studied. The manufacturing of the boards used residues from a 13 year old radiata pine tried with an average diameter of 14 cm and a height of 20.3 m., and for the Olivillo boards residue from a felling site of Roble-Laurel-Lingue, with average diameters of 25.8 cm and 100 to 150 years of age was used. Twenty-four boards, of a single layer, 11 mm. thick and with density of 600 kg/m 3 , were made from each of the two species considered. Ureaformaldehyde was the adhesive used with a binder factor of 9% b.o.d.w. The hydrophobic substance used, was a parafine emulsion which was applied at five different concentrations b.o.d.w. of the particles, the lowest being 0.5% and the heighest being 2.5 %. By including hydrophobic substances into the boards, their physical properties improve notably. However, the hydrophobe produced a slight decrease in the recorded mechanical resistance of the boards, particulary those of traction, which was not, however, significant. With a level of up to 1.5% of parafine emulsion added to the boards, adequate physico-mechanical properties were attained which also reached the values established by the corresponding norms.

This paper presents an inventory method for natural forests, using a double-sampling scheme with data from plots as well as aerial photographs. This method proved useful for assessment of native forest timber volume.