The aim of research was to determine peculiarities of relations between mature layer of the stand with distribution of spruce (Picea abies. Kr.) regeneration according phenology forms and growth specifics. The study examined the success of the resumption of spruce in the Leningrad region under the canopy of the parent stand. In stands with different share of spruce and in various forest-typological conditions, the features of the relationship between the maternal canopy of the stand, the distribution of the natural resumption of spruce by phenological forms and its course of growth were investigated. The account of the undergrowth was carried out by two methods: continuous reading and selective-statistical method. Regardless of the state of viability of spruce undergrowth, the increase in success of regeneration goes from a late vegetation season growth start form to an early one. Under the canopy of the maternal tree stand, young spruce of the early form has the best growth and development indices. In general, under the canopy of spruce stands, the annual height increment in spruce undergrowth, regardless of the phenological structure, the size categories and the state of viability, is greater than under the canopy of pine, pine-spruce and birch-spruce stands. The best characteristics of spruce undergrowth, regardless of phenological forms in vaccinio-myrtillo-pinetum type of forest are described. When analysing the characteristics of spruce undergrowth under the canopy of the stand, taking into account the phenological and altitudinal structure, and the state of viability, it was revealed that at the average age prevailing in the spruce undergrowth of the transitional form, the best parameters of growth have small and medium forms and growth in the early form. Analysing the characteristics of spruce undergrowth under the canopy of the stand, taking into account the phenological and height structure, as well as vitality status, it was revealed that at average age, dominating for the spruce undergrowth of transitional form, the best parameters of small and medium groups of undergrowth has early vegetation season growth start form. The best parameters of the growth have a large group of undergrowth of late vegetation season growth start form.

The regeneration of European hornbeam (Carpinus betulus L.) has been assessed in the National Gene Reserve Forest near Lukne in the south-western part of Latvia, which is the northernmost point of hornbeam distribution in Europe. In the studied stand, six sampling plots and four transects were established to assess stand structure and the effect of irradiation parameters on stand regeneration. Successful regeneration of hornbeam was shown by its presence in all height and diameter classes. Nevertheless, in the smallest height and diameter classes, an increased abundance of other shade tolerant species (maple (Acer platanoides L.) and lime (Tilia cordata Mill.) was observed. Norway spruce (Picea abies Karst.) mainly formed a scattered second forest floor and, apparently, competed with hornbeam. Light parameters, particularly, the diffuse radiation, had a significant effect (p=0.05) on the distribution and abundance of hornbeam understory. The threshold values of irradiation parameters for hornbeam were notably higher compared to other species. The number and height of hornbeam saplings correlated tightly with the amount of available light. Nevertheless, under sufficient light conditions hornbeam showed good vitality, thus suggesting suitability of growing conditions.

Northern Europe will be one of the locations where the renewable energy from forests could displace fossil fuels as a result of climate change: therefore, it will become more crucial to maintain renewable materials that also collect CO2. By taking tree biomass out of forest stands, we could create more renewable resources to use in practice, but this has certain negative effects on the forest ecology, including nitrogen leaching and vegetation degradation. The goal of the study is to investigate the effects of full biomass removal (FBR) in Norway spruce (Picea abies (L.) H. Karst.) forest stands and how this forest management affects vegetation regeneration, tree stock and carbon storage overall. The aforementioned structures were assessed at various forest ages. The central region of Latvia contains Norway spruce stands with all of the sample sites under study situated on drained peaty mineral soils and weakly aerated gleyic soils. As a result of the long-term evaluation, it was determined that the forest vegetation in FBR was similar to that in the same-age control stand (SAC) and that vegetation can successfully regenerate. The average tree height and DBH is lower in areas where stump removal and understory biomass was not carried out. Statistically significant (p<0.05) long-term influence of stump removal on the average height and diameter of Norway spruce can be identified in all parameters, except, tree height in Myrtillosa mel. forest type. Total biomass removal in long term has almost no significant effect on tree stand and vegetation regeneration.