As worldwide trends are changing gradually and sustainable resources economy and reduction of hazardous emissions are coming to the forefront, several industry sectors are forced to revalue their resource consumption. The main emphasis is currently placed on the recycling of by-products. One of the methods, definitely, includes burning of by-products to generate power, however it is not always the most efficient one. By-products must be used in the manner that ensures that they provide high added value for the operation of the company and are environmentally friendly. This research focuses on the use of the by-products of birch (Betula) veneer manufacturing, in order to obtain thermal insulation material. The following characteristics of the wood fibre insulation material were determined: thermal conductivity, water absorption, vapour permeability, and prototype reaction to fire. The characteristics of the obtained wood fibre thermal insulation material: thermal conductivity 0.038 W•mE-1•kE-1; water absorption 12 kg•mE-2; the conformity of the material even to D fire reaction class was not determined. The principal conclusion: the wood fibre thermal insulation material conforms to the requirements set for thermal insulation materials.

Lodgepole pine (Pinus contorta) samples from three different provenances in Canada were investigated. All trees were the same age and had been grown in Latvia in similar conditions. Lodgepole pine of Summit Lake provenance had higher wood density (503 kg m-3) and a higher late wood content (46%) in comparison to Fort Nelson and Pink Mountain provenances. Investigation of chemical composition of wood indicated Summit Lake provenance wood as superior in cellulose content (49.7%), but no differences in lignin and extractives content were found between samples. Kraft pulp yield of Summit Lake samples (48%) was the highest, but the handsheet strength properties were relatively higher for pulp from Pink Mountain provenance pine wood.