1.1 Background of the work
Forests in Russia cover about 8 mill. km2 and over 20% of the global forest area (FAO 2015). Russian forests provide huge possibilities for wood harvesting and development of forest sector. However, since the Soviet Union times clear cut approach followed by insufficient thinning and regeneration practices have been widely used. As a consequence, the area of economically accessible forests has been reducing (Karjalainen et al. 2007, 2009). The lack of proper regeneration practices have also led to unfavorable forest succession, i.e. expansion of soft-laved deciduous tree species dominated stands (FAO 2012). Large availability of forest resources and market demand were favorable for such a development. However, new sustainability requirements ask for to improve existing management strategies.
In Moscow area, in forests hardwood tree species are dominant (about 58% of total growing stock volume), of which birches account 38%. The rest is softwood, the share of Norway spruce is 26% and that of Scots pine 21% of total volume of growing stock. The age structure of forests is following: 41 % of forests belong to the 2nd (41 – 80 years for conifers, 21 – 40 years for deciduous species) age class, whereas 3rd (81 – 120 years for conifers, 41 – 60 years for deciduous species) and 4th (> 121 years for conifers, > 61 years for deciduous species) age classes accounts about 20% each, and 1st (1 – 40 years for conifers, 1 – 20 years for deciduous species) age class only 15%, respectively (Forest plan of Moscow area 2008). Based on this, the current age structure of forests may not be optimal, which could be affected, however, by intensifying forest management.
Forest growth and, hence, also timber production and its economic profitability (NPV), are affected by many factors. First of all, prevailing climatic conditions and site fertility determine forest growth potential. However, various tree species have also different preferences to climatic and site conditions, which affect nutrient and water availability of trees, respectively. Thus, proper site-specific choice of tree species in forest regeneration, considering environmental (climate, site) conditions is essential (Melekhov 2003). Different forest management options are also available to improve the growth and structure of forests. Thinnings may be used to enhance growth of crop trees and to decrease natural mortality. Different rotation lengths may be used to achieve desired size (diameter) of trees at final cut.
Management regimes used affect also the profitability of forestry. Reasonable shortening of rotation periods and use of commercial thinnings help to get earlier incomes, and may increase the profitability of forestry, especially in case of high interest rate. Though, forests are also vulnerable to many damages due to natural disturbances. In young seedling stands, especially frost, insects, and mammals, may cause damage. In older stands, there may exist wind- and snow induced damages, pests outbreaks and wood decay by pathogen species. Additionally, forest fires may cause damage regardless of forest age. All these risks could be at least partially diminished by means of appropriate forest management practices (Seidl et al. 2017, Reyer et al. 2017).
Forest management is in Russian Federation regulated by Forest code (so called forest law), and forest management rules, which contain region specific forest management recommendations. Those documents determine appropriate methods for forest regeneration, timing and intensity of thinning and rotation lengths. According to official statistics, 88% of reported forest regeneration activities in Moscow area are done artificially, however, resulting in an insufficient growth of the main tree species, especially Scots pine (Forest plan of Moscow area 2008). Artificial regeneration is done by planting of seedlings or seed sowing, latter one on sites with a weak development of grass cover. Natural regeneration includes protection of viable undergrowth of the main tree species, seed trees and soil preparation (by harrowing, scarification and moulding).
Recommendations for choice of regenerable tree species are following: pine and birch could be regenerated regardless of site fertility type, but spruce is preferable on more fertile sites. Then, tending of seedlings is recommended to be done to enhance crop trees growth, 2 or 3 times until 20 years age.
Commercial thinning operations could be done many times during rotation, however, at the latest 20 – 30 years before final felling (clear cut). Intensity of thinning varies from 10 to 30% of volume of growing stock, the actual value being determined by basal area thresholds. Rotation lengths vary depending on tree species, forest usage category and region. Generally there are two types of forest usage categories: protection forests and production forests. The main function of production forests is to produce high quality wood and other forest resources. Rotation length in this forest category is 80 – 100 years for conifers and 60 – 70 years for birch in a mixed forests zone (Ob ustanovlenii vozrastov rubok 2015). Forests related to protection category should be maintained primarily in order to preserve environmental, water-conservation, protective,
sanitary-and-hygienic and other useful functions of forests (Forest code of Russian Federation 2006). These forests have longer rotation periods. All forests in Moscow area refer to protection category. Thus rotation length for conifers is 100 – 120 years and for birch 70 – 80 years (Forest plan of Moscow area 2008).
In general, recommendations for forest management practices in Russia and Finland, and particularly in Moscow area and Central Finland, are rather same. However, artificial regeneration is more common in Finland compared to natural regeneration.
Also there are differences in implementation of commercial thinnings. In Finland, they are less frequent, but more intensive. Rotation lengths are shorter in Finland, i.e. 70 – 80 years for conifers and 60 years for birch, depending on site fertility, e.g. in central Finland (Äijälä et al. 2014).
Forest management recommendations in Finland are affected by targets given for timber production (high saw log yield) and its profitability, considering interest rate of about 2-3%. Oppositely, there is no assessment of the cost-effectiveness of the proposed activities in Russian forest management plans (Karjalainen et al. 2007). Decisions made in forestry, based on old Growth and Yield tables and regulations, don’t take either into account economic profitability. Thus, to improve the profitability of forestry and to fulfill the sustainability requirements of forest management practices, new decision support tools are needed.
One of the goals mentioned in Forest plan of Moscow area, as published by the Federal forest agency, is to enhance forest productivity and profitability of forestry. Decision support tools may help to choose an appropriate management regime in a given forest ecosystem and economic conditions. The lack of decision support tools in forest management planning in Russia makes profitability analysis and comparison of different forest management options quite difficult.
However, impacts Russian forest management regulations may be possibly evaluated also using modeling tools developed in other countries, if they are suitable and calibrated to Russian conditions. The information available for past growth and yield tables for forests, e.g. in Moscow area, could be used to support the calibration of available forest growth and yield models in order to predict future forest growth and timber supply potential and economic profitability of different forest management options. So far, it has not been widely used growth simulators to predict timber yield in
practical forestry in Russia. However, there have been some previous attempts to adapt existing foreign decision support tools for Russian conditions. For example, some previous attempts exist using Finnish MOTTI stand simulator, under “KARELIA ENPI CBC PROGRAMME 2007-2013” (Sukhanov et all. 2012).
1.2 Aims of the work
In this work, it was studied the effects of alternative forest management regimes on development of volume of growing stock and timber yield (pulp wood and saw logs) and its economic profitability (NPV with different interest rates) in Scots pine (Pinus sylvestris), Norway spruce (Picea abies) and Silver birch (Betula pendula) stands on different site fertility types under the current climate in Moscow area. This was done based on simulations with a forest ecosystem model (SIMA), which was originally developed in Finland (by Kellomäki et al. 2008), and calibrated in this study for the Moscow area. In simulations, it was used as inputs, stand characteristics reported in old growth and yield tables, and Finnish management (thinning) recommendations for practical forestry and Russian management (thinning) recommendations. Additionally, no management (thinning) option was simulated. In all cases, the final felling (clear cut) was done at same stand age. Based on this work, it was aimed to find out if the current Russian forest management regulations are the most beneficial from the economical point of view or are there better management options available.