Stand-replacing disturbance does not directly alter the succession of Norway spruce regeneration on dead wood (original) (raw)

Natural regeneration in narrow strip clear-cuts of Norway spruce (Picea abies L.) stands

Baltic Forestry

The rate of natural regeneration of Norway spruce and birch in narrow strip clear-cuts in Norway spruce stands between 25 to 30 years of age in South Sweden, and the relationships between rate of regeneration and environmental conditions have been studied in order to find the best methods of natural regeneration. First year regeneration was evaluated by counting seedlings within circle sample plots located on scarified belts within strip clear-cuts. About 14.5 % of total variation in the rate of spruce regeneration and 12.7 % in the rate of birch regeneration were due to peculiarities of stands and strip clear-cuts. The rest of variation was due to within strip clear-cut variation of micro-site ecological conditions. In separate stands the correlation between the regeneration rate and some ecological factors studied varied due to differences between these stands. There was found very weak negative correlation between the regeneration of spruce and the width of strip. The correlation...

Natural development and regeneration of a Central European montane spruce forest

Forest Ecology and Management, 2010

Montane Norway spruce forests of Central Europe have a very long tradition of use for timber production; however, recently there has been increasing concern for their role in maintaining biological diversity. This concern, coupled with recent severe windstorms that led to wide-spread bark beetle outbreaks, has brought the management of montane spruce forests to the forefront of public policy discussions in Central Europe. In order to shed light on the natural development and current structure of mature montane spruce forests, we established four 0.25 ha research plots in a semi-natural montane spruce forest in thě Sumava Mountains (The Bohemian Forest), Czech Republic. We mapped all trees, extracted increment cores for age and growth-pattern analyses, and inventoried all current tree regeneration, including the substrates on which it was found. Stands were characterized by uni-modal tree diameter distributions and high basal areas (56.6 m 2 ha −1 on average), indicating a natural transition from the stem exclusion phase towards the understory reinitiation phase. The stands showed largely single-cohort recruitment age structures, however, with recruitment spanning seven decades. Our analyses suggest that this cohort existed as advance regeneration prior to major disturbances in the late 1800s, which included post-bark beetle salvage logging. Spatial pattern analyses of living and dead stems combined, showed an increase in uniformity of living trees, pointing to the role of natural density-dependent mortality. However, past growth patterns and historical documentation suggest that low intensity canopy disturbances (wind and snow) also caused mortality and diversified canopy structure. Because the stands developed naturally over the past 120+ years and thus escaped thinning operations, high volumes of coarse woody debris (94 m 3 ha −1 ) and snag densities (546 stems ha −1 ) have accrued. Advance spruce regeneration was quite abundant and existed primarily on deadwood substrates, even though these occupied only a small percent of stand area. Because of salvage logging in the late 1880s, these stands do not qualify, according to the traditional paradigm, as natural spruce forests. As a result, they are recently subject to active management practices including salvage logging that remove dead and dying trees. Given the importance of deadwood for forest regeneration and recovery from disturbance, as demonstrated in this study, we argue that dead wood removal may limit future natural regeneration in these stands. Thus, the purported benefits of removing dead and dying trees from semi-natural forests must be carefully weighed against the potential detrimental impacts on natural spruce forest regeneration and biodiversity.

Natural regeneration in Central-European subalpine spruce forests: Which logs are suitable for seedling recruitment

Decaying logs form the major seedbed for trees in European subalpine Picea abies forests. However, many aspects related to seedling colonization pattern on logs remain unclear. The aim of this study was to analyze the relationships of P. abies (Norway spruce) seedling (height <15 cm) and sapling (height P15 cm) densities on decaying logs in relation to stage of wood decay, log diameter, ground contact of decaying log, assumed cause of tree death, presence of species of wood-decaying fungi and coverage by surrounding plants in the subalpine old-growth forests of the Bohemian Forest and Ash Mountains, in the Czech Republic. We have focused on how logs with different origin differ in their properties and how these properties influence seedling abundance. Seedling densities peaked on the medium-decayed logs and decreased thereafter. Sapling densities continually increased as the decay progressed. Seedling and sapling densities followed negative binomial distributions, with many logs of all decay stages having low regeneration densities. The degree of ground contact, white-rot-causing Armillaria spp. presence, white-rot-causing Phellinus nigrolimitatus presence and log diameter were positively related to both seedling and sapling density. Also tree death as a result of wind uprooting was positively related to sapling density. Conversely, the presence of brown-rot-causing Fomitopsis pinicola and tree death as a result of bark beetle attack were negatively related to regeneration densities. The low cover of vegetation from sides positively affected seedling density; however, heavily covered logs were less occupied by seedlings.

Natural regeneration of Norway Spruce (Picea abies (L.) Karst.) stands on northern Velebit

Background and Purpose: Natural regeneration is a natural phenomenon that depends on numerous factors. Regeneration of virgin forests is successful even without any human interference. For the regeneration of economic forests we do not have that much time and thus try to speed up the process. The study of factors involved in natural regeneration as the most perfect system of forest ecosystem regeneration requires long lasting research. Material and Methods: Numbers and heights of seedlings and new growths, as well as the species participating in natural regeneration were measured on four test plots over the period of four years (1995, 1998, 1999, 2000). The plots were located at different elevations and contained different plant communities. The Norway spruce seed yield and its quality (germination) were also researched. Results: Very poor appearance of seedlings and new growth and even the decline in the numbers were observed on all test plots. This can be directly correlated to ma...

Growth of advance regeneration of Norway spruce after clear-cutting

Tree Physiology, 2005

We developed a basal area growth model for recovery of advance growth of Norway spruce trees after clearcutting. Stem diameter growth at ground level and needle-mass characteristics were measured on permanent sample plots in Estonia. Both tree ring analysis (destructive sampling on one sample plot) and yearly repeated measurement data (two plots) were used to quantify advance growth. Basal area growth of small trees was estimated by multiple regression analysis. Previous-year basal area of the tree and basal area growth explained tree performance the next year. Tree needle-mass variables characterizing the acclimation status of the tree were included in the model as explanatory factors. Needle samples (one shoot from the upper third of each tree crown) were collected each year after the growth period from all sample trees. Needle masses of shoots from consecutive years were correlated and this variable was used as a predictor in the simulation model. Accelerating growth was observed in trees that exceeded the growth threshold in the year after release: the greater the needle mass per shoot, the greater the acceleration in growth. Competition among advance regeneration trees was included in the model: small trees under taller neighbors exhibited reduced growth. We found that trees released from a long period of heavy shade can survive, but the time needed for acclimation and resumption of competitive growth rates is considerably longer than for trees released from light shade. Such trees can be used for forest regeneration, but competition control (particularly reducing the proportion of fast-growing hardwoods) is required.

Advance Regeneration of Norway Spruce and Scots Pine in Hemiboreal Forests in Latvia

Forests

Continuous cover forestry (CCF) aims to emulate small natural disturbances and take advantage of natural regeneration. To implement these management practices successfully, knowledge of advance regeneration under the canopy in different conditions is crucial. Therefore, the aim of this study was to assess the influence of stand inventory parameters of canopy layer (age, basal area, height, and density) on the probability and density of advance regeneration of the Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.) in hemiboreal forests in Latvia. The data were obtained from the National Forest Inventory, from a total of 879 plots. In the study, only Norway spruce or Scots pine dominated stands were used and the sampled stand age ranged from 21 to 218 years. The probability of advance regeneration differed between stands dominated by Scots pine versus Norway spruce. The probability and density of the advance regeneration of Norway spruce were positively li...

Development and dynamics of mountain spruce (Picea abies [L.] Karsten) stand regeneration

Journal of Forest Science

We summarized development and dynamics of natural regeneration in mountain spruce forests in areas affected by bark beetle gradation in the Šumava National Park. Detailed measurements of the regeneration were carried out using Field-Map technology (www.fieldmap.com) on ten permanent research plots. Research plots included the forests with decaying tree layer, stands in partial decline and stands with a generally healthy, or only partially damaged tree layer. Differences in rates of regeneration are very significant between the particular types of plots, especially in the youngest age class. Differences are also evident in the seedling height under varying treatments. The highest numbers of recruits (9,880 per ha) were found under intact overstorey canopies, while the fastest height growth occurred on clearcuts. This study also investigated and evaluated artificial regeneration done in the past.