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2021 > 05

Svartberget field technicians Hassan Ridha and Ellika Hermansson measure the growth and overall condition of spruce trees in a previous trial. Photo: Andreas Palmén. Svartberget field technicians Hassan Ridha and Ellika Hermansson measure the growth and overall condition of spruce trees in a previous trial. Photo: Andreas Palmén.
Cooperation with landowners is vital for SITES research focused on sustainable forest management. For example, in a new silviculture project, researchers from SLU, in cooperation with Skogforsk and forest companies, will take an experimental and novel approach on the establishment of pine stands in northern Sweden. Field technicians from Svartberget Research Station will be responsible for the establishment and future monitoring of the field trials.

In total, 19 silvicultural trials will be established over a period of two years on forestland of varying fertility. For some trials, many years have passed since the actual felling. The aim is to study the long-term effects of tree species, soil preparation, reforestation method and plant-fertilization.

Recent inventories of young stands in the interior of Norrland have revealed low stem and quality stem numbers per hectare. In particular, many young pine stands show trees severely damaged by, among other things, moose grazing and fungal infections. The so called multi-damaged pine forests means a large loss in future production. In some cases, the stands are so damaged that the best option is to start all over again. This is very costly for landowners and there is no guarantee that the same problems won’t arise again.

Thus, it is important to avoid previous mistakes in silviculture. The experiments will compare several potential establishment alternatives to improve the knowledge of producing young stands.

Two main alternatives will be tested. One based on various measures to accelerate the height growth of the pine plants which would reduce the time they are susceptible to moose grazing. Using an excavator to prepare mounds that allow for group planting is one such example.

The other alternative to be tested is the use of other tree species like Norway spruce, Silver birch, Russian larch (a.k.a. Siberian larch) and Lodgepole pine. Species comparisons in production are either rare or unfavourable. Spruce suffer less from grazing and are not sensitive to the fungal damages that affect pine. To avoid the low production of spruce compared to pine seen on many locations in the interior of Norrland, plant fertilization of spruce will be tested. Birch is relatively untested in the area, while stands with Russian larch often have shown good results in growth but comparisons are lacking. Experimental results and experience regarding site selection and silvicultural methods are very limited for both. Lodgepole pine is relatively common in the area and avoided by game for grazing.

There are extensive trials where the higher long-term production of Lodgepole pine compared to Scots pine is evident, but the wood quality and stability of planted Lodgepole pine on fertile soil may be questionable. Mixed sowing of pine and Lodgepole pine can therefore be a way to increase the probability of having a high production stock with a sufficiently high number of undamaged stem.
Location of the deployed pressure gauge south of Bolmsö island.  The pressure gauge was installed at a water depth of approximate 1 m. Photo: Clemens Klante. Location of the deployed pressure gauge south of Bolmsö island. The pressure gauge was installed at a water depth of approximate 1 m. Photo: Clemens Klante.
In a new project, the wave climate at Lake Bolmen will be investigated to gain new insights about the hydrodynamics of the lake and the waves’ effect on water quality. Recent measurements of water pressure will be used to help to calibrate and validate wave models, which will be a helpful asset for analysis of current and future conditions.

Lake Bolmen is Skåne’s most important drinking water resource. The lake’s ecology and chemical status has changed during the last decades and some of these changes could negatively affect water quality. One of the most noticeable changes is the effect of brownification, resulting in yellow to brown colored water due to the increase of humic substances and iron leachate from the catchment. One aim of the Bolmen Research station is to create knowledge that helps to sustain Bolmen as reliable water resource, ecosystem and place for recreation. Therefore, further insight into changes to water quality is important.
The pressure gauge (the tube) before deployment. The gauge is strapped to a stone (ca.25kg) that ensures that it does not change in position, neither in height nor place. Photo: Clemens Klante. The pressure gauge (the tube) before deployment. The gauge is strapped to a stone (ca.25kg) that ensures that it does not change in position, neither in height nor place. Photo: Clemens Klante.
One factor influencing water quality is the hydrodynamics and the wave climate (see fact box below) of the lake. This is because waves mainly determine transport and mixing conditions through the whole lake and within the water column. Due to Lake Bolmen's relatively large size (183 km2), waves induced by wind are likely to occur, but specific knowledge about them is limited. With the application of a wave model, that later will be combined with a general hydrodynamic model, a better understanding of Lake Bolmen’s hydrodynamics will be gained.

Recently conducted measurements of water pressure will help to calibrate and validate this model. Even though measurements have only been recorded on a single side of the lake, the contribution is rather large as this is the first real measurement of this kind. In addition to the simulation of the present wave climate at Lake Bolmen, analysis of future conditions due to changes in climate and ice cover will be conducted.

In the future the wave measurements will be extended and additional water quality measurements at different locations within the lake will be conducted. This will allow a more detailed combined analysis of water quality changes and interactions with hydrodynamics and the wave climate present at Lake Bolmen.
 
Text: Clemens Klante, Sweden Water Research and Lund University.

Wave climate
Wave climate is defined as the distribution of wave height, period, and direction averaged over a period of time for a particular location.

Source: Herbich J.B., Walters T. (1987) Wave climate. In: Climatology. Encyclopedia of Earth Science. Springer, Boston, MA. https://doi.org/10.1007/0-387-30749-4_195

One of the tree seedling plots that has been established at Lönnstorp. Photo: Tarquin Netherway. One of the tree seedling plots that has been established at Lönnstorp. Photo: Tarquin Netherway.
A new project will investigate the role of plant traits and mycorrhizal on plant-soil feedback as well as on microbial community assembly and functioning during seedling establishment. Experiments will be done at the two SITES agricultural stations and therefore include agricultural land in southern and northern Sweden.

The project at Lönnstorp and Röbäcksdalen research stations aims to answer questions around the relative importance of different woody-plant traits, such as leaf and root habits, together with mycorrhizal associations (symbiotic root associations with fungi) for plant-soil feedback mechanisms (i.e. the growth response of plants when growing in a new soil habitat) and for structuring soil, root and leaf-associated microbial communities and their functioning.
 
To investigate this, seedlings of twelve different woody plant species, ranging from conifers, such as spruce, and yew to broadleaf species, such as birch and maple, will be transplanted. The different species associate with different mycorrhizal fungi. Some seedlings will be inoculated with forest soil and some will not. Seedlings will also be planted in soil from the station where they are not planted (i.e. some seedlings at Lönnstorp will be planted in soil from Röbäcksdalen and vice versa) to account for differences in abiotic and biotic factors between the two sites.
 
The growth of the plants will be measured over two growing seasons, during which leaf associated microbial communities and nutrient concentrations will be analyzed. At the end of the experiment rhizosphere soil will be collected to examine the chemical properties and the microbial communities.
 
The results will hopefully contribute to the knowledge about which traits of the plant-soil system are central in altering the growth habitat (negatively or positively) during afforestation. In addition, these results could give an indication of the implications on ecosystem processes such as carbon and nutrient cycling across different climates over the short term, together with unravelling basic ecological questions around the assembly of plant-associated microbial communities and their functioning.  
 
Text: Tarquin Netherway, Department of Ecology, SLU.
Developing shoot of Norway spruce at Asa. Photo: Martin Ahlström. Developing shoot of Norway spruce at Asa. Photo: Martin Ahlström.
Even though arctic winds have reduced the temperature outside, spring is on its way. And with the spring approaching, so is the seasonal start of the Phenology monitoring programme at Asa research station.  

Phenological observations are made on birch, spruce and pine trees as well as on bilberry and lingonberry bushes. Shoot development, autumn leaf colouring, leaf felling and flowering are followed as part of the phenological observations. The monitoring programme started in 2006.
 

Example data from Asa Phenological Monitoring

Relative number of flowers, unripe and ripe berries of lingon, according to phenology assessments made in Asa between 2006 and 2020. Lines represent the 15-year average (solid) and standard error (dashed) numbers. Left panel show number of flowers, unripe and ripe berries vs. date and right panel vs. temperature sum, calculated from air temperature at standard height from the meteorological station in Asa.
 

Relative number of flowers, unripe and ripe berries of bilberry, according to phenology assessments made in Asa between 2006 and 2020. Lines represent the 15-year average (solid) and standard error (dashed) numbers. Left panel show number of flowers, unripe and ripe berries vs. date and right panel vs. temperature sum, calculated from air temperature at standard height from the meteorological station in Asa.
 

Shoot development of Norway spruce, according to phenology assessments made in Asa between 2006 and 2020. Pink dashed lines indicate single year development, black lines represent the 15-year average (solid) and standard error (dashed) shoot development. Left panel show shoot development vs. date and right panel vs. temperature sum, calculated from air temperature at standard height from the meteorological station in Asa.
 

Shoot development of Scots pine, according to phenology assessments made in Asa between 2006 and 2020. Pink dashed lines indicate single year development, black lines represent the 15-year average (solid) and standard error (dashed) shoot development. Left panel show shoot development vs. date and right panel vs. temperature sum, calculated from air temperature at standard height from the meteorological station in Asa.

Photo: Ola Eriksson. Photo: Ola Eriksson.
At the Abisko Scientific Research Station (ANS) the vehicle fleet was recently expanded with an “ark”. Here, Magnus Augner, station manager, tells what an ark is and why it was acquired.

Up here in Norrbotten, an "ark" is a kind of living module, usually with a stove, which you pull out on the lake ice with a snowmobile. In the floor of the ark there is a hatch through which you can do ice angling, while you have a nice time in the warmth inside.
 
A few years ago, Håkan Grudd, deputy station manager, got the idea that arks might be something for our Antarctic expeditions. He contacted several manufacturers and in the end we decided on Järvsöarken. A special feature of their arks is that you can place a snowmobile inside the ark, which is a great advantage for transport and storage for a longer period of time.
 
After some discussions, they built three arks for us, which were then adapted to our needs in Antarctica, with e.g. snow melter, stove that allows cooking and solar cells for charging batteries. In the field season 2017-18, we used them for the first time on an expedition and it was clear that this was a good concept for expeditions into "deep field", i.e. so far away from research stations that one has to be self-sufficient, with the exception of fuel depots. Each "two-people set" consists of two snowmobiles, an ark, and a snowmobile sled (for fuel, research equipment, food, etc.)
Photo: Ola Eriksson. Photo: Ola Eriksson.
Why snowmobile arks? A large cost and a clear environmental impact is the fuel that must be transported down to Antarctica in order to conduct all types of activities. Looking for light-weight solutions that also have a high level of security is always an important part of our development of Antarctic logistics. Being able to live "indoors" in a warm space, which does not take time to set up, makes life on expeditions much more comfortable and safer than living in a tent.
 
In order to primarily be able to show and test living in arks during field courses, we have also purchased an ark for ANS. This also provides possible support for researchers who want to be able to live in the field in winter, away from the station and our field cabins.
 
Version 2 of our ark is 20 cm wider than the first one, which means that the beds are now 60 cm wide instead of 50 cm. The ark is equipped with fire extinguisher, carbon monoxide alarm, fire blanket, lighting, solar cells, 12v battery, USB charging, inverter 230 V, stove etc. In short, a small well-equipped "caravan" for snowmobiles, where two people can live quite comfortably.

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