In Russian practical forestry, growth predictions are done based on growth and yield tables. Previous studies dealing with development of forests in Russia under alternative management regimes used statistical models (like FORRUS-S (Chumachenko et al. 2003, 2004), EFIMOD (Shanin et all. 2009)). In this work, it was analyzed 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, Norway spruce and Silver birch stands on different site fertility types under the current climate in Moscow area based on simulations with a forest ecosystem model, which was first calibrated to Russian conditions.
Model calibration was done based on real growth and yield data from Moscow region and climate observations from local meteorological station over the period 1962-1984.
The average difference between measured and predicted values did not exceed 15%, which is acceptable. Thus, generally, the performance of a gap-type forest ecosystem model SIMA in Moscow area was reasonable. These results suggest also that the SIMA model may be used in the Moscow area conditions at least with a reservation.
Nevertheless, further development of model is needed in order to use it as a decision support tool in forest management planning in Russian conditions.
The climate data used in this work was rather old (1962 – 1984 years). So if assume climate change happened since that period, then these climate observations would be not representative currently. However, if assume that the above mentioned climate change did not lead to drastic shifts in growing conditions and, hence, did not cause growth degradation of any species, then changes should be positive. It means, that in this study tree’s growth may be slightly underestimated. Nevertheless it still allows making comparisons between different management regimes and development of different tree species.
Model stand data was based on old growth and yield tables based on data from sample plots established in 1936-1940 and 1946. However, these tables are still representative compared to current state of forests in Moscow area. The choice of alternative management regimes was based on ongoing discussions regarding advantages and disadvantages of Finnish and Russian forest management practices (Petrov at all. 2018).
Despite the fact that that both schemes are similar in principal (include regeneration and thinning operations during rotation), there are noticeable differences in intensity of thinning operations leading to different growth and yield results. The No management regime was taken into account as it is a common practice in Russia.
NPV calculations were done in order to compare profitability of above mentioned regimes. Calculations were based on stumpage prices for different timber assortments in Central region of Russia. Costs of pre-commercial thinning were not considered in the calculations as they were assumed to be done manually by the forest owner. However, the effect of pre-commercial thinning costs on final NPV was discussed. The study results provide comparisons for pure even-age stands of main forest tree species of Moscow area under current climate. No climate change or natural disturbances were considered. This causes limitations on the use of research findings in practice.
4.2 Case study results
The key finding was that Finnish management recommendations led to the highest productivity and profitability of forests. This result could be explained by 10 to 30%
more intensive commercial thinnings applied in Finnish forest management practices compared to Russian recommendations. That result also corresponds with earlier results on the influence of different thinning intensities on the average inventory indices for spruce (Belyaeva, Ishchuk 2014) and pine (Zalesov et all. 1193), this claims that medium and high intensity thinning results in the highest effective stand productivity.
Another noticeable difference between Finnish and Russian forest management is number of thinning operations. In Finland commercial thinning are usually done from 2 to 3 times during rotation with time span of 20 to 30 years. In Russia commercial thinning should be done every 10 to 20 years during rotation. Sennov (1987) argued that reasonable reduction in the number of thinnings facilitates maintenance and makes it more profitable. At the same time, frequent thinnings are dangerous for the forest health, as they are associated with heavy machinery going into forest and possible damages of standing trees. Stem and root damage may lead to wood decay caused by Heterobasidion annosum especially on spruce stands (Isomäki and Kallio 1974). Thus, Finnish forest management recommendations appeared to be more profitable compared to Russian one.
No management regime, as expected, resulted in lowest total volume of harvested timber and, hence, lowest profitability. The absence of early incomes from commercial thinnings made unmanaged forest almost twice less profitable compared to managed one. However if consider high interest rate and costs of pre-commercial thinning, then No management regime could become the most profitable option, if applied on less valuable stands, e.g. birch stands. Under above mentioned conditions Russian regulations led to losses on less fertile (MT) sites and birch stands. Though, under moderate (4%) interest rate Finnish management recommendations remain to be the most profitable.
However, the results could be different if take into account natural disturbances and climate change. Management practices may increase or decrease susceptibility of forest stand to different natural disturbances. Intensive thinnings increase the probability of wind damage (Lohmander and Helles 1987; Peltola 1996), while lack of thinning operations may lead to forest fires due to accumulation of dead wood on forest floor (Recommendations for fire prevention 1997). Bark beetle induced damage could be caused by both active and passive forest management. Bark beetle outbreaks usually associated with weakened forest stands or high amount of suppressed trees in unmanaged stands (Maslov 2010). Active forest management may cause damage of remaining trees leading to various diseases and make them vulnerable to bark beetles (Nazarov 2002).
Climate change is also likely to affect the performance of alternative management regimes. According to recent-generation (CMIP5) global climate model projections average annual temperature would increase by 3,4 °С in Central federal region of Russia under moderate (RCP4.5) scenario (Roshydromet 2014). Precipitation may also increase by about 38mm year-1, but not in summer, thus the temperature increase and resulting moisture deficit would lead to increasing number of drought periods. A lot of research has been done on how climate change may affect forest growth in Finland. In Southern Finland the growth in spruce especially but also partially in pine may decrease under severe climate change (Kellomäki et al. 2018). Similar consequences could be expected in Moscow area as the trends of climate change are the same in both regions.
Due to higher winter temperatures the depth of soil frost may decrease and soil frost periods may shorter. That would negatively affect soil bearing capacity during winter season and, thus, make harvesting operations problematic (Lehtonen et al. 2018). These
risks to forests and forestry should be taken into account when designing forest management activities and making decisions.
4.3 Conclusion
Based on this study, there may need to increase thinning intensity of Russian forest management, to increase profitability. Finnish forestry experience could be used as support for this change. However, there are a lot of uncertainties associated with climate change, natural disturbances and slow return on investments as mentioned in Senko (2018). These factors should also be considered in further research.