Forest recovery in set-aside windthrow is facilitated by fast growth of advance regeneration

Key message

The disturbance of a research plot by a windstorm allowed us to study the role of the seedling bank in the regeneration processes. The released advance regeneration dominated among the saplings; taller individuals retained their position until the end of the study. Pioneer species occurred sporadically. Seven years after the disturbance, the windthrow was covered by a dense thicket of young trees.

Context

The dominant role played by advance regeneration in natural regeneration processes after intense wind disturbances is still a matter of dispute.

Aims

We took advantage of a windstorm in one of our research plots to study the role of the seedling bank released by the disturbance in the regeneration processes.

Methods

We collected data in 70 plots, recording the survivorship of seedlings, annual height growth, and signs of browsing. The height ranking was analyzed with Kendall’s concordance coefficient, and the height growth rates were compared using Dunn’s test.

Results

The density of seedlings increased from 6.7/m² in 2008 to 8.1/m² in 2010 and then decreased to 1.2/m² in 2015. The density of saplings increased continuously from 0.14 to 1.9/m². The highest size differentiation occurred in sycamore maple; the individuals which were taller before the windstorm retained their position until the year 2015. The only species that was recruited mainly from germinants was European hornbeam.

Conclusion

The advance regeneration released by the windstorm played a major role in the regeneration process, while pioneer species occurred only sporadically. Seven years after the disturbance, the windthrow was already covered by a dense thicket of young trees.

     

Patterns of bark beetle occurrence in Norway spruce stands of national parks in Tatra Mts. in Poland and Slovakia

This paper presents the results of a research project concerning bark beetle populations in Norway spruce stands managed under a nature protection regime in national parks in Tatra Mountains in Poland and Slovakia. The preliminary data on bark beetle occurrence and related selected stand characteristics are presented. The dynamics of a bark beetle outbreak that occurred from 1994–97 in the stands localized on both sides of the state border and in various nature protection regimes is analyzed retrospectively. The data concerning the tree/stand characteristics, i.e. DBH and increment of trees are discussed in relation to its potential role in the mechanism for the spread of bark beetle populations. The patterns of the spatial distribution of trees attacked during the research period (1999–2001) are described.     

Patterns of bark beetle occurrence in Norway spruce stands of national parks in Tatra Mts. in Poland and Slovakia

This paper presents the results of a research project concerning bark beetle populations in Norway spruce stands managed under a nature protection regime in national parks in Tatra Mountains in Poland and Slovakia. The preliminary data on bark beetle occurrence and related selected stand characteristics are presented. The dynamics of a bark beetle outbreak that occurred from 1994–97 in the stands localized on both sides of the state border and in various nature protection regimes is analyzed retrospectively. The data concerning the tree/stand characteristics, i.e. DBH and increment of trees are discussed in relation to its potential role in the mechanism for the spread of bark beetle populations. The patterns of the spatial distribution of trees attacked during the research period (1999–2001) are described.     

Role of environmental filtering and seed source availability in natural regeneration processes following large-scale disturbances in mountain forests

European Journal of Forest Research - The relative importance of environmental factors and species pool in natural regeneration processes is still intensively disputed. Is environmental filtering...     

Factors limiting the synthesis of virgin olive oil volatile esters

The aim of the present work was to establish the limiting factors affecting the biosynthesis of volatile esters present in virgin olive oil (VOO). Oil volatile fractions of the main Spanish olive cultivars, Arbequina and Picual, were analyzed. It was observed that acetate esters were the most abundant class of volatile esters in the oils, in concordance with the high content of acetyl-CoA found in olive fruit, and that the content of C6 alcohols is limited for the synthesis of volatile esters during the production of VOO. Thus, the increase of C6 alcohol availability during VOO production produced a significant increase of the corresponding ester in the oils in both cultivars at two different maturity stages. However, the increase of acetyl-CoA availability had no effect on the VOO volatile fraction. The low synthesis of these C6 alcohols seems not to be due to a shortage of precursors or cofactors for alcohol dehydrogenase (ADH) activity because their increase during VOO production had no effect on the C6 alcohol levels. The experimental findings are compatible with a deactivation of ADH activity during olive oil production in the cultivars under study. In this sense, a strong inhibition of olive ADH activity by compounds present in the different tissues of olive fruit has been observed.     

α-Thujone exhibits an antifungal activity against F. graminearum by inducing oxidative stress,apoptosis, epigenetics alterations and reduced toxin synthesis

European Journal of Plant Pathology - Specific mechanisms contributing to the antifungal activity of α-thujone, one of the main compounds of essential oils in herbs, against Fusarium...     

Impacts of soil conditions and light availability on natural regeneration of Norway spruce <Emphasis Type="Italic">Picea abies</Emphasis> (L.) H. Karst. in low-elevation mountain forests

? Key message

Natural regeneration of P. abies (L.) H. Karst. may reach high densities in lower mountain elevations. The highest densities were found in sites with moderate light availability, with low pH, and not near the riverbank. However, age-height classes differed in the predicted magnitude of response, but were consistent in response directions. Mosses and understory species typical of coniferous forests were positively correlated with regeneration density.

? Context

Norway spruce Picea abies (L.) H. Karst. in Central Europe is at risk under climate change scenarios, particularly in mountain regions. Little is known about the impact of environmental factors on the natural regeneration of P. abies in low-elevation mountain forests.

? Aims

We aimed to assess impacts of distance from the riverbank, soil pH, and light availability on natural P. abies regeneration. We hypothesized that (1) natural P. abies regeneration would depend on light availability and soil pH and (2) there are understory plant species which may indicate the microsites suitable for natural regeneration of P. abies.

? Methods

The study was conducted in the Sto?owe Mountains National Park (SW Poland, 600–800 m a.s.l.). We established 160 study plots (25 m²) for natural regeneration, light availability, soil pH, and understory vegetation assessment.

? Results

The highest densities of natural regeneration of P. abies were observed in sites with moderate light availability (0.1–0.2 of open sky) and low pH (3.5–4.5), and located relatively far from the riverbank. Cover of 22 understory plant species were correlated with natural P. abies regeneration densities, mostly positively.

? Conclusion

Different stages of natural regeneration of P. abies revealed different regeneration niches. Most understory plant species (bryophytes and herbs typical of coniferous forests) do not compete with natural regeneration of P. abies.

     

Patterns of bark beetle occurrence in Norway spruce stands of national parks in Tatra Mts. in Poland and Slovakia

This paper presents the results of a research project concerning bark beetle populations in Norway spruce stands managed under a nature protection regime in national parks in Tatra Mountains in Poland and Slovakia. The preliminary data on bark beetle occurrence and related selected stand characteristics are presented. The dynamics of a bark beetle outbreak that occurred from 1994–97 in the stands localized on both sides of the state border and in various nature protection regimes is analyzed retrospectively. The data concerning the tree/stand characteristics, i.e. DBH and increment of trees are discussed in relation to its potential role in the mechanism for the spread of bark beetle populations. The patterns of the spatial distribution of trees attacked during the research period (1999–2001) are described.