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The objective of this thesis was to determine how aspen (Populus tremuloides Michx.) root systems and suckering are affected by decking area (site of log processing and storage) disturbances and seasonal timing of these disturbances. In a field study, summer-built log decks reduced regeneration by half compared to fall-built decks, and if decks were built in the fall, 11 month and 1.5-3 month storage were similar in their impact. A growth-chamber study examined the timing of traffic-induced wounding of the root system and simulated log storage on aspen root systems and suckering. For both summer and winter treatments the combination of root wounding and log storage killed nearly the entire root system and prevented suckering. Root wounding and log storage alone caused a 35-40% reduction in living root mass, carbohydrate reserves, and sucker growth. Sucker numbers were reduced by one half for the winter but were unaffected for the summer.

Colour and appearance of hardwood are of great importance for the interiorand furniture industry. The widespread use of transparent surface treatmentand a fashion that prescribe light colour on many species, means that deviationfrom the ideal have considerable impact on the industrial operations. Kilndrying is generally regarded as the process that has the greatest impact on thecolour of Nordic hardwood species. The lack of satisfactory explanation modelsfor many types of discoloration, however, complicates the control of the dryingprocess.This thesis is an attempt to increase the knowledge of which factors thatcontrol the appearance of some commonly found discolorations associated withdrying of beech, birch and oak. The main focus is on convection drying but alsothe influence of timber storage, pre-steaming and press drying has beeninvestigated for individual species. The studies have been conducted ascomparative studies based on design of experiments in which the colour wasdetermined using a colorimeter.Results show that reddish and dark discoloration of beech and birch duringconvective drying is mainly dependent on the temperature and time of exposurewhen the local moisture content exceeds the fibre saturation point. Theconversion of naturally occurring substances in birch into coloured compoundsis not due to active precursors created at high moisture content levels duringthe subsequent drying at low moisture content levels. Interior grey stain inbeech is caused by slow initial drying at low temperatures. Log storage in coldwinter and spring climate does not cause discoloration in beech. Birch becomeslighter when press-dried at high temperatures, resulting in a colour comparableto that of traditionally kiln dried wood. Steaming of oak before kiln dryingreduce the presence of brown discoloration, a general darkening of the woodoccurs at temperatures above 50°C.