Dispersal of Norway spruce and Scots pine seeds from the forest edge
Miskininkyste (2(52)): 81-88
The dispersal patterns of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) seeds from the forest edge in Lithuania, as well as the speed of seed dispersal depending on the moisture of the cones were studied. There was no significant difference in the timing of opening of cone scales in response to decrease of moisture content in cones between pine and spruce. Seed dispersal started when the moisture content of the cones dropped to 17-18%. Full opening of the scales occurred when the moisture content of the cones was less than 10%. On the average, seeds of pine and spruce fell down at the speed of 1.44 and 1.29 seconds/m, respectively. In the absence of wind, seeds of pine and spruce fell in vertical direction, which means limited spread to new areas. In spring, seeds of pine and spruce were dispersed in approximately two months. Under natural conditions, 32% of the total number of pine and 30% of spruce seeds dispersed fell directly under the crown. Whereas, only 1.2% pine and 2.9% spruce seeds reached the distance of 110 m from the seed source. The main part of the seeds were dispersed in 20-30 m from the forest edge, which was approximately equal to the height of the mother trees. Precipitation has a stronger effect on spruce seed dispersal than temperature. In contrast to spruce, seed dispersal of pine was greatly influenced by the mean daily temperature.