Current issue: 58(4)
We used forest ecosystem model simulations to study how forest conservation and management intensity affected timber yield, ecosystem carbon stocks, amount of dead wood, and habitat suitability area in a middle boreal forest region of Finland under changing climate over a 90-year simulation period. We used the following forest conservation and management scenarios: baseline forest management (BM), BM with 10 or 20% increase of conservation area with or without intensified forest management (i.e. improved forest regeneration material and forest fertilization). The simulations were done under current climate (reference period of 1981–2010), and Representative Concentration Pathway (RCP) climate change projections under the RCP2.6 and RCP4.5 forcing scenarios. Overall, increasing the forest conservation area decreased timber yield and increased the ecosystem carbon stock, the amount of dead wood and consequently the area of suitable habitat for saproxylic species. The use of intensified forest management reduced the loss of timber yield, increased ecosystem carbon stock, the amount of dead wood and area of suitable habitat for saproxylic species. At the end of simulation period, the use of intensified forest management even overcompensated (4–6% higher) the timber loss from 10% increase of conservation area. Under changing climate, timber yield, the amount of dead wood and the area of suitable habitats for saproxylic species increased. To conclude, with intensified forest management it is possible, in the short term, to decrease the loss of timber yield through increased forest conservation area and in the long term maintain or even increase it compared to baseline forest management.
This study compares the responses of two Swedish 5-year predictive stand-level functions with the observed responses in 721 fertilization experiment plots in Norway fertilized with nitrogen (N). All plots are single-species consisting of Norway spruce (Picea abies (L.) H. Karst.) or Scots pine (Pinus sylvestris L.) fertilized with ammonium nitrate (AN) or urea. The correlations between the observed and the two predicted responses were 0.34–0.40 for all plots taken together. One response function performed well on average, but underestimated the response in pine plots and overestimated the response in spruce plots. The second function overpredicted the response on the full dataset, in spruce plots and old forest, but performed well in pine plots. Both functions overestimated the growth response in high-productive plots. Higher N deposition in Norway than in Sweden may count for parts of the deviations. Testing of fertilization functions on new datasets is rare, but important part of the evaluation of functions. As the functions are not well fit for predicting the growth response in spruce and high-productive plots in our sample, new functions that include N deposition are welcome.