Current issue: 53(4)
Under compilation: 54(1)
The pine weevil Hylobius abietis L. is an economically important pest insect that kills high proportions of conifer seedlings in reforestation areas. It is present in conifer forests all over Europe but weevil abundance and risk for damage varies considerably between areas. This study aimed to obtain a useful model for predicting damage risks by analyzing survey data from 292 regular forest plantations in northern Sweden. A model of pine weevil attack was constructed using various site characteristics, including both climatic factors and factors related to forest management activities. The optimal model was rather imprecise but showed that the risk of pine weevil attack can be predicted approximatively with three principal variables: 1) the proportion of seedlings expected to be planted in mineral soil rather than soil covered with duff and debris, 2) age of clear-cut at the time of planting, and 3) calculated temperature sum at the location. The model was constructed using long-run average temperature sums for epoch 2010, and so effects of climate change can be inferred from the model by adjustment to future epochs. Increased damage risks with a warmer climate are strongly indicated by the model. Effects of a warmer climate on the geographical distribution and abundance of the pine weevil are also discussed. The new tool to better estimate the risk of damage should provide a basis for foresters in their choice of countermeasures against pine weevil damage in northern Europe.
Britain has the smaller proportion of woodland than almost any other country in Europe. During the two World Wars strategic considerations led to an examination of the adequacy of the national forest resources. A Forestry Commision was set up and the state started to promote the expansion of forestry. In the second war-time examination of the national forest policy, the Forestry Commision set an aim that after 50 years there would be about 5 million acres of productive woodland. However, the aim was not reached. During the Second World War there was large inroads into the remaining growing stock. The post-war policy recognized a need to new emphasis to reforestation, and two Forestry Acts were enacted in 1945 and 1947 to speed up the planting program.
In 1947 there was 3,448,362 acres of forests in blocks of five acres or over, and 184,000 acres in smaller woods. 82% of these were owned by private forest owners. The area of high forests was 1,788,799, coppice 349,994, scrub 496,994, devastated land 151,064 and felled 665,554 acres. The objective is that forestry in Britain should eventually supply about a third of the annual requirement. The 1947 act introduced the Dedication Scheme, which for instance provides grants and loans for the forest owners for forest management work, and states some obligations concerning forestry.
The expansion of forestry was shaped by ideas of national safety in time of war rather than buy achieving profit. Presently, the main economic task is to build up the national forest industry.
The Acta Forestalia Fennica issue 61 was published in honour of professor Eino Saari’s 60th birthday.
Distribution, biodiversity and reforestation dynamics of the platyphyllous forests in the Northwest European Russia were investigated. Data assembled from 21 landscape regions (250–350 km2 each) show special features of small-leaved lime (Tilia cordata Mill., Norway maple (Acer platanoides L.), mountain elm (Ulmus glabra Mill.) and English oak (Qurecus robur L.) reforestation during the last two decades. New tendencies were found for the taiga areas with natural Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.) vegetation. Natural platyphyllous reforestation in cut spruce areas poses as supposed a special question for forest management policy in the relationship to global climate changes. Feasible unsustainability of the common types of succession (Norway spruce - European birch (Betula pendula Roth); Norway spruce - European aspen (Populus tremula L.)) is discussed. Biodiversity of herbs, shrubs and tree species of platyphyllous forests is high and complex and is situated in 4–15 old-growth relics in each landscape region. Low-level genotype heterogeneity of nemoral flora species of such isolated populations is presumed. Special biodiversity conservation regulations are proposed.
The economic analysis is based on computer simulations which covered a seedling rotation and three successive coppice rotations. Calculations were carried out for the four site productivity classes in Eucalyptus globulus plantations. The rotation length that maximized the land expectation value is 12–20 years for seedling rotation and 8–16 years for coppice rotations with discounting rates 2–8%. The mean wood production is over 40 m3/ha/a in the best site class and about 10 m3/ha/a in the poorest class with rotation lengths ranging from 10 to over 20 years. Thinnings increase the wood production and land expectation value by a few percentage points. In areas suitable to Eucalyptus globulus growth, the land expectation value is considerably higher in forestry than in agriculture, except in very poor areas or with very high rate of interest.
The PDF includes an abstract in Finnish.