Epsilon Archive for Student Projects

Abstract

The dilemma of climate change, biodiversity conservation and economic efficiency in nowadays forestry leads us to search for the new solutions. Introduction of non-native tree species becomes a more frequently explored field as a solution for the future problems. However, introduction is limited by adaptability, susceptibility and productivity which all together control the success and risks of their potential. This thesis studies three native and nine introduced tree species planted in tree species experiments across the low, moderate and high site productivity gradients in southern Sweden. Evaluated native species are Norway spruce, Scots pine, silver birch and introduced- white spruce, black spruce, Sitka spruce, lodgepole pine, Douglas fir, grand fir, balsam poplar, hybrid larch, hybrid aspen. The early growth of tree species provides us a better understanding of potential and expectations in the following growth periods. Besides the native tree species, a few of the non-native species such as lodgepole pine or Douglas fir have already been introduced in Swedish forestry. But for others, such as grand fir, black spruce or white spruce research is rather scarce.
Evaluation included a review of the species-specific literature on ecology, soil preference, growth and known biotic/abiotic risks as well as the early-growth analysis and comparison of diameter, height, basal area and total volume between and inside the low, moderate and high productivity sites in the southern Sweden.
Among the studied native species, based on total volume growth, Scots pine was most productive in low productivity, while Norway spruce- in moderate and high productivity sites. In comparison silver birch produced lowest total volume out of the three native species.
In the low productivity site volume growth of hybrid larch and lodgepole pine was higher than of the Scots pine, Douglas fir growth was similar to the growth of Norway spruce, while white spruce total volume growth was the lowest.
In the moderate productivity site Sitka spruce, grand fir and hybrid larch productivity was higher than of the Norway spruce. Hybrid aspen productivity was similar to Norway spruce. The lowest productivity was measured in black spruce and Douglas fir plots, not reaching either of the native species.
In the high productivity site, the highest production was measured by grand fir, there as Sitka spruce, balsam poplar and hybrid larch total volume growth were similar to the Norway spruce. Douglas fir total volume was slightly higher than of the silver birch, although was significantly lower than of the Norway spruce. Fast-growing hybrid aspen total volume by the age 18 was equivalent to the growth of Norway spruce by the age 30, showing the high suitability for short-rotation plantations.