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A Benchmark Workshop for Demersal species (WKDEM), chaired by External Chair Richard D.M. Nash, UK and ICES Chair Daniel Howell, Norway and attended by two invited external experts Amy Schueller, US and Robert Boenish, US met at ICES, HQ, Copenhagen 9–13 December 2019 for a data evaluation meeting and at ICES HQ, Copenhagen, Denmark, for a Benchmark meeting 10–14 February 2020. In addition, two WebEx meetings were convened (23rd October 2019 and 23rd February 2020) to discuss data issues and logistics related to the work plan prior to the data evaluation meeting and the Benchmark.Four demersal stocks were Benchmarked in WKDEM, Haddock (Melanogrammus aeglefinus) in subareas 1 and 2 (Northeast Arctic) (Had.27.1–2), Cod (Gadus morhua) in Division 6.a (West of Scotland) (Cod.27.6a), Whiting (Merlangius merlangus) in Division 6.a (West of Scotland) (Whg.27.6a) and Whiting in Division 3.a (Skagerrak and Kattegat) (Whg.27.3a).The 2020 benchmark for Northeast Arctic Haddock was proposed due to the poor retrospective pattern (annually changing perception of the stock) for the assessment in 2018. The final SAM model was based on the updated dataset and a new SAM setting allowing for plus groups in surveys. The final model had a lower AIC and more parameters compared to the configuration used in the previous assessment with the same data as the final model. Some changes were made to the prediction models, mainly to reflect the current perception of the stock dynamics. The reference points were not changed.The 2020 benchmark for 6.a cod was proposed initially due to uncertainties in the catch data and the selectivity patterns in the catch and survey data. In addition, a separate analysis of the stock estimated a different trend in fishing mortality and higher biomass, which lead to an inter-benchmark in February 2019. A number of alternative assessment methods were considered with a decision to switch from the TSA model to SAM. An improved approach to estimating area-misreported landings was implemented, and maturity and natural mortality values were modified. The survey data included in the final assessment are consistent (in terms of year and age range) with those used previously. The reference points were updated having been derived following the ICES guidelines and using EqSim. There was some concern that an alternative model, FAFmodel, along with an extension to allow natural mortality to be estimated by the model (“TVM” model) provided a different perception of the stock dynamics. The latter model was not presented for evaluation prior to the Benchmark and as such needs to be evaluated as to its efficacy for assessment of this stock in the future.The 2020 benchmark for 6.a whiting was proposed because the assessment was influenced partly by incorrect reporting of landings data (species and quantity) from the past which directly affected the perception of the stock. There were newly available catch data and reworked survey indices (including the combined Irish and Scottish Q4 survey), plus reworked maturity and natural mortality estimates were available. It became clear that running TSA with the new data and changed survey configuration resulted in poorly converged optimisation runs. An age-aggregated stochastic Surplus Production in Continuous Time (SPiCT) model was tried but the modelled stock level was highly uncertain, although the trends were considered more robust. The result was to reclassify 6.a whiting to category 3 using the SPiCT model to give trends, according to the ICES guidelines for data-limited stocks.The 2020 benchmark for 3.a whiting was proposed because it was considered a category 5 stock with no advice and more information is available (time-series of catches (landings and discards), a new fisheries independent biomass index that combines all relevant scientific surveys in the area) that were not being used but could be utilised to infer stock status and provide better catch advice. The outcome was to reclassify the stock to category 3 and provide advice using the “2-over-3” trend based approach with the new biomass index. An attempt to provide an analytical assessment for the stock using the surplus production model (SPiCT) was unsuccessful.

In the natural stands of the lower−montane zone in the 'Łopuszna Valley' Reserve (Gorczański National Park) consisting of beech, fir and spruce, a specific phenomenon was observed, which in other natural forests of the Western Carpathians occurred only occasionally. In the years 1981−2011, along with the increase in the proportion of beech in stands and in regeneration, which is now common issue in the forests of Central Europe, an increase or stability in the proportion of fir in stands and an increase in the proportion of fir in the undergrowth was reported. At the same time, the number of spruces in stands clearly decreased, while in the regeneration they occurred sporadically. Reduction in the proportion of spruce leads to a change in the species composition of multi−species stands i.e. from stands with co−dominant beech, fir and spruce to stands with dominant beech or co−dominant beech and fir. In managed forests, it is necessary to maintain the prevalence of all tree species for their productivity, which requires the application of the best silvicultural practices (regeneration and tending)., Sylwan 157 (3): 213-222

In the study period 1997−2007, the current volume increment in three fir−beech stands in the maturing stage equalled to 6.4−7.3 m/ha/year, and in fir stands in the optimum phase it was 13.8 m/ha/year. The loss of volume was high and showed wide variation among the study sites from 3.1 to 12.6 m/ha/year. A larger number of fir recruits in this period compared to beech recruitment and the increased fir volume increment rate over the previous 10 years on Walusiówka and Ociemne study sites suggests that the decrease in the proportion of fir noted from the beginning of the research in the Pieniny Mountains (1974) was halted, or might even start change into the increase over time., Sylwan 156 (3): 182-191

Sylwan 151 (6): 34-52

The specific of widely understood natural conditions of the montane forests and the functions they serve indicate the need of promoting more complex, non−schematic and improved forest management methods than in the lowlands. Depending on the species composition the renewal of forests of the lower mountain zone requires application of regular shelterwood systems – often in a modified form (beech and spruce stands), irregular shelterwood−group system, Swiss irregular shelterwood system, and where possible, selection system (in fir stands). In the spruce stands of the high mountain zone the mountain selection system is recommended. Conversion of pure spruce stands and nurse crops should be a long−term process using the silvicultural procedure based on some of the above−mentioned regeneration methods. Tending of the advance regeneration and thickets depend on stand stability and production aim (spruce), site conditions and site quality (beech), variability of structure and origin of regeneration (fir) should be closely connected with regeneration methods. In the maturing stands the following thinning methods should be applied: in spruce stands – Wiedemann, Abetz, as well as Burschel and Huss thinnings; in fir stands – crown and selection thinnings; in beech stands – selection and group thinnings. The group method of planting (rot system) ensures the most successful forest regeneration at high altitudes in the mountains., Sylwan 147 (2): 3-19

The causes of changes in the growth of European single− and multi−species stands that have been recently reported are seen in the changes in land use including forests, the effect of silvicultural management methods including the use of fertilisers and liming, natural disturbances, damage caused by game, changes of climatic conditions particularly the impact of the global climate warming, as well as air−borne deposition., Sylwan 147 (7): 69-74

The paper provides information concerning the growth of pine, spruce, oak, beech and fir stands based on the research conducted by the European Forest Institute in a number of the European countries and in Poland. Noteworthy i.a. is the increase in volume increment of spruce and pine in some stands in Germany up to 250% of the values given in the yield tables. Since the early fifties of the past century beech and sessile oak in Bavaria have exhibited an increase in the height growth and volume increment. Their values markedly exceed those provided in the tables. Fir, similar to spruce, pine and beech shows the reduction in the increment and dieback in the regions under heavy industrial pollution. However in other regions under the impact of air pollution the response of pure and multispecies stands with the share of fir was positive. In Poland, a rapid decline in the dbh increment in three tree species (fir, spruce, pine) in the seventies was greater than in the sixties. In 1981−1989, fir showed a favourable growth in diameter; this positive tendency was noticed in the whole range of fir distribution in Poland, though the increment did not return to the level before its decline. The pine increment regenerated after 1990. The poorest increment was found in spruce in the eighties following its collapse in the seventies (Żywiecki and Śląski Beskid)., Sylwan 147 (6): 99-106