Influence of sapling height and temperature on damage to advance regeneration

The increased interest in natural regeneration during the last decade has highlighted the importance to minimise the amount of damage to the understory, i.e. the advance regeneration, when harvesting the overstory. Unfortunately damage to the advance regeneration cannot be totally avoided. In order to evaluate the effects of sapling height and temperature on the risk of fatal damage on saplings, spruce (Picea abies (L.) Karst.) saplings were bent in a controlled experiment. Results show that the probability of breakage increased with sapling height and decreasing temperature. Some practical advices for forest operations based on the results are that harvesting of the overstory during low temperatures and driving in and felling of trees towards areas with high regeneration should be avoided. (C) 2002 Elsevier Science B.V. All rights reserved.