Of the ca 130 delegates, one half were researchers and the others representatives of industry, the authorities and the media. The generally good presentations ranged from the past to the future. During the first session we could see that knowledge has undergone tremendous progress. For example, one researcher who was a contemporary of Linné claimed that there were plenty of moose in Africa.
Fewer pines
Kjell Danell of SLU also talked about moose, but those in Sweden. He described the large increase in moose stock from the middle ages, and pointed to management as a very successful preservation project. Christer Kalén from the National Board of Forestry did not, however, think that the project was so successful, at least from the standpoint of silviculture. Moose and roe deer destroy young pine forests in the south of Sweden to such as large extent that forest owners almost always plant only spruce today, he pointed out.
He warned that there may be large losses in production, since spruce grows much worse on some soils than pine, and reinforced his message with the help of Harry Martinson:
"Pine, the tall tree with its crown as a lookout at the top, ranges over our endless inland sea of spruce where, year after year and wave after wave, for the rest of our lives, we can count how spruce vanishes among spruce" (Tuvor, Bonniers 1973).
Root rot and pine nematode
Both pests known for a long time, such as root rot, pine weevil, spruce bark beetle and pine rusts, and recent arrivals such as the pine wood nematode that is a potential threat, were discussed.
Climate changes allow more southerly species to penetrate further north. One frightening example, in which both human management measures and a warmer climate have played a part, was reported by Staffan Lindgren of the University of Prince George, British Columbia: In Canada, the mountain pine beetle has in just a few years damaged 14 million hectares of mainly lodgepole pine, an area that corresponds to more than half the forest land area in Sweden. This aggressive insect attacks only large live trees, and an attack can be stopped only by a very cold winter or the absence of any more live trees to attack. According to Lindgren, control of forest fires and successive mild winters have aggravated the problem.
Christer Björkman of SLU objected that it is not obvious that the risk of attack by poikiothermic insects increases as the climate warms. He said that it is governed by a complex interaction among insect pests, predatory insects and host plants, and he gave the example of the larch tortrix in the Alps whose attack diminished as it became warmer.
Many insect pests migrate through human trade, for example through wood packaging. The pine wood nematode is a new worrying species on the European continent. It kills pine and was found for the first time in 1999 in Portugal where it has now spread over increasingly large areas. The EU Seventh Framework Programme contains a call for applications concerning this danger.
Author
:
Hans-Örjan Nohrstedt
is Director of International Affairs, Formas