Carbon Stocks of Hardwood Floodplain Forests along the Middle Elbe: The Influence of Forest Age, Structure, Species, and Hydrological Conditions

Hardwood floodplain (HF) forests can store a considerable amount of carbon (C), and floodplains may be good candidates for reforestation to provide natural C sinks. In this study, we use nondestructive inventory methods to estimate the C stocks of different tree species and C pools within HF forests of varying age and structure and located at sites differing in hydrological conditions (low and high active floodplain, seepage water zone, tributaries). The study was carried out along the Elbe river (Germany). Average C stocks for young plantations in the active floodplain were significantly lower (50.2 ± 10.8 SE Mg ha−1) than those of old dense (140.6 ± 11.6 SE Mg ha−1) and old sparse forests (180.4 ± 26.6 SE Mg ha−1) with comparable hydrological conditions. C stocks of old dense forests did not significantly vary from old sparse forests. Additionally, C stocks of old forests did not significantly vary according to hydrological conditions. The highest amount of C was stored in Quercus robur for all hydrological conditions. Ulmus laevis stored the second-highest amount of C on the active floodplain. We conclude that sparse and dense forests as well as forests under different hydrological conditions provide the same C storage function.

Assessing forest management scenarios on an Aboriginal territory through simulation modeling

The dominant management strategy in boreal forests—aggregated clearcuts (AC)—faces increased criticism by various stakeholders, including Aboriginal people. Two alternative strategies have been proposed: dispersed clearcuts (DC) and ecosystem-based management (EM). We modelled the long-term and landscape-scale effects of AC, DC, and EM on a set of indicators of sustainable forest management relevant to an Aboriginal community's values: (1) forest age structure; (2) spatial configuration of forest stands; (3) road network density; and, (4) forest habitat loss to clearcuts. EM created a forest age structure closer to what would result from a natural disturbance regime, compared to AC and DC. Cut blocks were more evenly distributed with EM and DC. The road network density was lower and increased slower with EM, thus reducing the potential for conflicts between forest users. Under EM, a higher forest cover was maintained (and thus potential wildlife habitat) than in AC or DC. The EM scenario provided the best outcome based on the four measured indicators, partly because the constraints imposed on the modeling exercise led it to harvest less than the other scenarios. Annual allowable cut should thus be a key factor to consider to ensuring better compliance with Aboriginal criteria of sustainable forest management.

Reconstructing European forest management from 1600 to 2010

Because of the slow accumulation and long residence time of carbon in biomass and soils, the present state and future dynamics of temperate forests are influenced by management that took place centuries to millennia ago. Humans have exploited the forests of Europe for fuel, construction materials and fodder for the entire Holocene. In recent centuries, economic and demographic trends led to increases in both forest area and management intensity across much of Europe. In order to quantify the effects of these changes in forests and to provide a baseline for studies on future land-cover–climate interactions and biogeochemical cycling, we created a temporally and spatially resolved reconstruction of European forest management from 1600 to 2010. For the period 1600–1828, we took a supply–demand approach, in which supply was estimated on the basis of historical annual wood increment and land cover reconstructions. We made demand estimates by multiplying population with consumption factors for construction materials, household fuelwood, industrial food processing and brewing, metallurgy, and salt production. For the period 1829–2010, we used a supply-driven backcasting method based on national and regional statistics of forest age structure from the second half of the 20th century. Our reconstruction reproduces the most important changes in forest management between 1600 and 2010: (1) an increase of 593 000 km2 in conifers at the expense of deciduous forest (decreasing by 538 000 km2); (2) a 612 000 km2 decrease in unmanaged forest; (3) a 152 000 km2 decrease in coppice management; (4) a 818 000 km2 increase in high-stand management; and (5) the rise and fall of litter raking, which at its peak in 1853 resulted in the removal of 50 Tg dry litter per year.

Emulating boreal forest disturbance dynamics: Can we maintain timber supply, aboriginal land use, and woodland caribou habitat?

The effects on timber supply incurred by implementing an ecosystem-based management strategy were evaluated in an eastern Canadian boreal forest management unit. Standard linear programming was used to test the effects of four key policy issues: (1) aim for a targeted forest age structure inspired by natural fire regime and forest dynamics (multi-cohort approach), (2) agglomerate harvest blocks in operating areas to reproduce natural disturbance patterns at the landscape scale, (3) maintain cumulated clearcutting and natural disturbance rates inside the historical range of variability, and (4) exclude from harvest areas of potential interest to aboriginal people. The targeted forest age structure was achieved with a minimum reduction of periodic timber supply, but only after 50 years. Compared to a “business-as-usual” scenario, inclusion of the first three policy issues resulted in a 3% to 11% reduction in planned timber supply and a restoration period requiring that 43% to 67% of the productive area be excluded from clearcutting activities for the next 50 years. Such results require that partial cutting not be confined to operating areas eligible for clearcutting. Further exclusion of forest areas of potential interest to aboriginal people resulted in an additional 4% to 10% decrease in planned timber supply. Validation of the coarse filters used in this study (first three policy issues) was done using habitat requirements of woodland caribou (Rangifer tarandus caribou). Almost all scenarios induced a disturbance rate likely to allow a self-sustaining woodland caribou population within 25 years.