Generally, our present understanding of what determines forest management intensity is weak, particularly at broad scales, and this makes it difficult to assess the environmental and social trade-offs of intensification. In this post, I would like to present you the research of international scientists who have analyzed spatial patterns of forest harvesting intensity in Europe.
Introduction
A forest use in Europe has a long history, what makes it an interesting case for assessing forestry intensity. After centuries of extensive deforestation, Europe’s forests increased in the 19th and 20th century as a result of farmland abandonment, afforestation, and nature protection, and forests now cover 37% of Europe’s terrestrial surface. According to Richard Fuchs from the University of Wageningen, forests and settlements grew at the same time and Europe is a much greener continent today than it was 100 years ago.
If you look at the above map, forest cover is distributed very unevenly across Europe and the region is furthermore characterised by large environmental (e.g., boreal to Mediterranean), historical (e.g., capitalism vs. socialism), ethnic, and economic (highly industrialised vs. less industrialised economies) heterogeneity. In the map you can also observe that forest cover has been increasing quite steadily during the last decades (ca. 0.37% per year, according to FAO), but forest harvesting intensity also remarkably has been increasing from 58% (1990) to 62.4% (2010) and it is expected to increase even further.
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This time, researchers from “the old continent” decided to analyse spatial patterns of forest harvesting intensity as one indicator for forest management intensity across Europe.
Methods
As intensity metric of forest management, scientists used the following ratio:
They used data from the period 2000-2010, and used boosted regression trees to quantify the influence of a set of biophysical, infrastructure, and socioeconomic variables in shaping these patterns.
Forest harvesting intensity in Europe – RESULTS
The results have shown that forest harvesting intensity varied in the analyzed period markedly across Europe. This result is probably up to date in present times due to heterogenity of Europe by itself.
Nevertheless, according to this research, the spatial patterns of average harvested timber volumes on the one hand, and our forest harvesting intensity index on the other hand differed substantially. Researchers noticed, that for example, southern Germany had generally high harvested volume levels (i.e., harvested timber volume per hectare forest), but relatively low forest harvesting intensity due to high forest productivity, whereas in southern Finland high forest harvesting intensity occurred despite lower harvest levels.
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C. Levers et al. noticed that harvested timber volumes are correlated with the productivity of forests, which is, to a large extent, explained by environmental conditions. Hence, the result of their research was quite interesting that the patterns in harvested timber volumes do not linearly translate into forest harvesting intensity, highlighting the potential usefulness of the intensity measure.
As researchers pointed, an increase in forest harvesting intensity was generally observable for Central Europe during the study period, whereas the intensity level of Scandinavian and Mediterranean countries remained largely constant.
Scientists wrote:
“Averaged over the period 2000–2010, regions with high forest harvesting intensity occurred in the southern parts of Finland, Sweden, Estonia, Czech Republic, as well as in Switzerland and smaller areas of northwest Spain, southwest and eastern France, and some scattered regions in Italy. Harvested timber volumes exceeded increment volumes substantially in some of these regions, for example, in southern Sweden and southwest France. Both, southern Sweden and the southwest of France suffered from severe storm events in the study period. Hence, subsequent salvage logging could explain high forest harvesting intensity.”
To sum up, this research showed that harvested timber volumes in Europe’s forests to be substantially lower than the net annual increment (Europe-wide approximately 60–65%), resulting in increasing forest growing stocks. Authors of the article pointed also, that many regions may have the capacity for future intensification of timber extraction without compromising the long-term sustainability in terms of wood yield. However, foresters and policy-makers should always bear in mind that aiming for sustainable use of forest resources, forest harvesting should not get close to or even exceed the annual increment of forests in the long run.
Source: Levers Ch. et al. 2014. Forest Ecology and Management 315 (2014) 160–172
Main photo: Trucking of timber in Poland. Author of the photo: Rafal Chudy
Measuring forest harvesting intensity becomes more interesting in the global scale. Current global harvesting volume is about 4 Gm3 (FAOSTAT) while the increment about 20 Gm3 (4000 Mm3 x 5 m3/ha). Hence, global average harvesting intensity is only 20%. For details look Lauri et. al (2017) (http://www.sciencedirect.com/science/article/pii/S1389934117300412)
or OECD data (https://data.oecd.org/forest/forest-resources.htm)
Thanks Pekka for an update, your comment gives a very clear picture that harvesting intensity, in the global scale, is still rather low. On the other hand, looking at the local scale, it varies from one extremes (completely not managed stands or hardly accessible) to another extremes (e.g. biotic and abiotic calamities).
Should be 4000 Mha (not Mm3). OECD data just EU28+Russia+USA+NZ -> miss all tropical areas.