Influence of ground substrate on establishment of reindeer lichen after artificial dispersal

Methods to improve the recovery of reindeer lichen after soil disturbance or overgrazing are being sought for areas where reindeer are herded. The effects of four substrates – mineral soil, moss, twigs and pine bark – on the establishment of lichen fragments after total removal of the vegetation were thus studied in a middle-aged pine stand and a clear-cut, both located in a lichen-rich pine-heath. Cladina mitis fragments of two sizes were manually dispersed in 1 m2 quadrats and their movements from their respective dispersal points were registered after one year. The natural re-establishment of lichens in the quadrats was monitored over three years by using digital pictures. In the forest stand, no significant differences were detected in either the fragment movement or the lichen establishment between the different substrates, but the fragment size had positive effects on both parameters. In the clear-cut, the moss substrate was the most suitable not only for the artificially dispersed lichens to fasten to, but also for the natural settlement of lichens from the surrounding lichen mat. More lichen thalli fastened to the bark and twigs substrates than to the mineral soil, but the settlement of lichens from the surrounding was greater on bare mineral soil substrate. The results indicate that artificial dispersal of lichen thalli on an appropriate substrate could be a successful strategy for promoting lichen recovery

Establishment of Cladonia stellaris after artificial dispersal in an unfenced forest in northern Sweden

In 2002, fragments and whole thalli of reindeer lichen, mainly Cladonia stellaris, were spread in a typical Scots pine forest in northern boreal Sweden to study the survival and development after artificial lichen dispersal. The forest was not fenced, allowing reindeer access to graze. Lichens were dispersed in intact vegetation in 1 m2 plots by one of two methods: either as an intact lichen mat (patch) of 0.25 m2 in the centre of the plot or as fragments scattered (scatter) across the whole plot. The lichen was then monitored by photo inventory. In 2006, three years after the first inventory, all patch plots had been partially grazed by reindeer and the lichen cover measured in both patch and scatter plots had decreased severely. In 2008, the lichen cover in the patch and scatter plots had increased by up to 54% and 88%, respectively, of the cover measured during the first inventory in 2003. A significant increase in the number of fragments in the plots was also observed between 2006 and 2008, suggesting that in addition to growing like naturally established thalli, the lichen had spread and slowly colonized the plots. Dispersing lichen by the “patch” method appears to be less costefficient than the “scatter” method, if the area is grazed by reindeer. These results support the hypothesis that dispersal of reindeer lichen could be an effective means of restoring lichen stands, which are important for reindeer husbandry, even if the area is open to reindeer grazing. Abstract in Swedish / Sammanfattning: Etablering av Cladonia stellaris efter artificiell spridning i ej inhägnad skog i norra Sverige Renlav (främst Cladonia stellaris) spreds manuellt 2002 i en talldominerad skog i norra Sverige för att studera lavens etablering efter artificiell spridning. Försöksområdet var inte hägnat utan öppet för renbete. Laven spreds i intakt markvegetation på 1 m2-ytor, antingen i form av intakta lavbålar (0,25 m2) i ytans centrum eller som fragment över hela provytan. Lavens etablering följdes med hjälp av fotoinventering. År 2006, tre år efter första inventeringen, hade alla provytor betats av ren och lavens täckningsgrad hade reducerats betydligt. Vid inventeringen 2008 hade lavens täckningsgrad ökat med upp till 54% (intakt lav) resp. 88% (lavfragment), i jämförelse med täckningsgraden den första inventeringen. Mellan 2006 och 2008 ökade antalet fragment per provyta signifikant vilket indikerar en fortsatt naturlig etablering med spridning via fragment. Att sprida lav i form av intakta lavbålar förefaller mindre kostnadseffektivt än spridning av lav i fragmentform om spridningsområdet är öppet för renbete. Resultaten utgör ett stöd för hypotesen att artificiell spridning av renlav kan vara ett effektivt sätt att restaurera viktiga renbetesområden, även om området inte är skyddat för renbete

Establishment of Cladonia stellaris after artificial dispersal in an unfenced forest in northern Sweden

In 2002, fragments and whole thalli of reindeer lichen, mainly Cladonia stellaris, were spread in a typical Scots pine forest in northern boreal Sweden to study the survival and development after artificial lichen dispersal. The forest was not fenced, allowing reindeer access to graze. Lichens were dispersed in intact vegetation in 1 m2 plots by one of two methods: either as an intact lichen mat (patch) of 0.25 m2 in the centre of the plot or as fragments scattered (scatter) across the whole plot. The lichen was then monitored by photo inventory. In 2006, three years after the first inventory, all patch plots had been partially grazed by reindeer and the lichen cover measured in both patch and scatter plots had decreased severely. In 2008, the lichen cover in the patch and scatter plots had increased by up to 54% and 88%, respectively, of the cover measured during the first inventory in 2003. A significant increase in the number of fragments in the plots was also observed between 2006 and 2008, suggesting that in addition to growing like naturally established thalli, the lichen had spread and slowly colonized the plots. Dispersing lichen by the “patch” method appears to be less costefficient than the “scatter” method, if the area is grazed by reindeer. These results support the hypothesis that dispersal of reindeer lichen could be an effective means of restoring lichen stands, which are important for reindeer husbandry, even if the area is open to reindeer grazing. Abstract in Swedish / Sammanfattning: Etablering av Cladonia stellaris efter artificiell spridning i ej inhägnad skog i norra Sverige Renlav (främst Cladonia stellaris) spreds manuellt 2002 i en talldominerad skog i norra Sverige för att studera lavens etablering efter artificiell spridning. Försöksområdet var inte hägnat utan öppet för renbete. Laven spreds i intakt markvegetation på 1 m2-ytor, antingen i form av intakta lavbålar (0,25 m2) i ytans centrum eller som fragment över hela provytan. Lavens etablering följdes med hjälp av fotoinventering. År 2006, tre år efter första inventeringen, hade alla provytor betats av ren och lavens täckningsgrad hade reducerats betydligt. Vid inventeringen 2008 hade lavens täckningsgrad ökat med upp till 54% (intakt lav) resp. 88% (lavfragment), i jämförelse med täckningsgraden den första inventeringen. Mellan 2006 och 2008 ökade antalet fragment per provyta signifikant vilket indikerar en fortsatt naturlig etablering med spridning via fragment. Att sprida lav i form av intakta lavbålar förefaller mindre kostnadseffektivt än spridning av lav i fragmentform om spridningsområdet är öppet för renbete. Resultaten utgör ett stöd för hypotesen att artificiell spridning av renlav kan vara ett effektivt sätt att restaurera viktiga renbetesområden, även om området inte är skyddat för renbete

Compression Processing and Load Compression of Young Scots Pine and Birch Trees in Thinnings for Bioenergy

In many boreal countries forest biomass from dense young stands has great potential to meet growing demands for bioenergy. However, there is currently no costeffective operational system for harvesting such stands. When harvesting, it would be desirable to compress trees and leave some of the foliage and fine branches in the stand in order to reduce extraction of nutrients and improve the harvested material's fuel properties from a reduced ash content point of view. The objectives were to evaluate experimental systems (a boomtip mounted unit for processing bunches, and a small prototype forwarder for compressing loads) in terms of their utility for compressing and partially debranching fresh and stored bunches of Scots pine trees and compressing forwarder loads of fresh Scots pine and birch trees. Processing of fresh bunches resulted in mass losses of about 10% (dbhclass 58 cm; not significant) to 15% (dbhclass 1215 cm; significant) with 35 to 50% reductions in ash contents and increases in bulk and net energy density of about 80 to 160%. Instand storage of bunches before processing generally yielded no significant advantages except for a 10%unit reduction in moisture content. Compression of forwarder loads resulted in 16 (pine) to 32% (birch) increases in load densities, with a significant increase for birch trees. The described techniques facilitate productivity increases of offroad and road transport of tree parts, and a substantial proportion of the ashrich materials such as needles and fine branches are left in the stand. If both tested techniques are applied during the harvesting of young trees the benefits would be substantial

Effects of intensity of forest regeneration measures on some ecosystem services in a nationwide Swedish field experiment

Effects on important ecosystem services (total and species-wise biomass production, distributed on tree fractions), of three regimes with different intensities of forest regeneration measures after clear-cutting were evaluated 24-27 years after initiation of a field experiment at 14 sites across Sweden. The three treatments, designated high (HI), normal (NI) and low (LI) respectively consisted of: mechanical site preparation and planting of large seedlings at 2 x 2 m spacing, with supplemental planting and pre-commercial thinning (PCT) when deemed necessary; standard local practices; and natural regeneration with no site preparation, artificial regeneration or PCT. Over all, significantly more total biomass was found in the HI (53.6 ton ha-1) and NI (40.8 ton ha-1) treatments compared to the LI (23.5 ton ha-1) treatment. For stem biomass, significant differences were found only between the HI and LI (37.0 and 16.5 ton ha-1, respectively) treatments, and the same result was also found for living branches; HI (8.2 ton ha-1) and LI (5.3 ton ha-1). For foliage, the two managed treatments had significantly higher values, 7.5 ton ha-1 (HI) and 6.3 ton ha-1 (NI) compared to 3.0 ton ha-1 for the LI treatment. Also for dead branches the highest value was found in the HI treatment (3.3 ton ha-1), significantly higher compared to the LI treatment (0.7 ton ha-1). In addition to effects on biomass production and allocation, the regeneration intensity also influenced stand structure and composition. Hence, regeneration intensity may affect biodiversity, ecosystem functions and social values in a number of different ways

Perspectives: Lean forestry-A paradigm shift from economies of scale to precise and sustainable use of ecosystem services in forests

Modern forestry practices are based on the idea of 'big is beautiful'. Especially in the regeneration phase, the operations are often excessive in relation to the profit that one can expect to gain in decades to come. Excessive operations also constrain the use of ecosystem services. Lean forestry is a novel philosophy of forestry practise that aims to direct the idea of "big is beautiful" in modern silviculture more into "do cost effectively only what is needed to fulfil the goals". To succeed Lean forestry requires exact spatial information to be able to carry out forestry measures very precisely only where they are really needed to fulfil goals. This kind of a paradigm shift requires systems with new kinds of abilities to remotely sense the surrounding environment and to make better and faster decisions based on sensed data. Automated unmanned offroad vehicle that is able to sense the environment and to make lean decisions is presented as an example of initiatives that can make forestry more cost-effective and simultaneously improve utilisation of wide range of ecosystem services in forests

Determining boreal clearcut object properties and characteristics for identification purposes

After clearcutting, machines traffic the clearcut conducting different silvicultural activities. Many objects on a forest clearcut (slash residues, stones, stumps and roots) may disturb e.g. site preparation and planting. This paper describes properties and characteristics of these objects. A flowchart was developed that describes a possible computer-aided system that identifies the objects, and ultimately, makes a machine avoid or target them. A system for obstacle identification creates conditions for further technical development and (semi)automation of e.g. site preparation, mechanized planting, and stump removal

Seedling and tree growth after Chequered-Gap-Shelterwood-Cutting and in conventional clear-cutting system

To achieve sustainability both ecological and production aspects need to be considered in forest management. Chequered gap shelter wood system (CGSS), consist of small clear-felled gaps with alternating areas of trees, giving the forest a chessboard appearance which potentially could combine the advantages from both the clear-cut system and continuous cover forestry. This approach will introduce more edges which might influence the effect of wind, temperature and solar radiation on seedlings and trees. In this study we evaluate 1) the influence of the forest edge and 2) the north- and south facing part in the gaps on the growth of seedlings and trees (Pinus sylvestris and Picea abies) in gaps and shelter forests, respectively, and compare the growth with that in a conventional clearcutting system. Overall, edges effected seedling growth negatively and tree growth positively. Seedlings also grew better at the northern sun exposed parts compared to the southern shaded parts of the gaps. As a consequence of these edge effects seedlings had a lower, and shelter trees a higher, growth in the CGS-system compared to the reference areas. Seedlings in the central part of the gaps grew better than seedlings in the reference area. Norwegian spruce seems to be the most suited tree species for this silvicultural approach. Given the contrasting effect of edges on seedlings and trees the production over the whole rotation need to be evaluated in future studies

Simulated productivity of conceptual, multi-headed tree planting devices

Mechanized tree planting is presently enjoying a revival in Fennoscandia with increased focus on further technical development. To explore the productivity effect of multiple heads on crane-mounted tree planting devices, we used a discrete-event simulation tool in which excavator-mounted one- to four-headed devices reforested clearcuts with variable frequencies of obstacles. During the simulations, the device models either mounded or inverted soil and then planted seedlings. A planting head could be hindered by stones and roots from performing these tasks, thus causing queuing delays for multi-headed devices. Surface boulders, stumps, and humus layers also slowed down the work. The results showed that productivity increased significantly with increasing numbers of planting heads on terrain with sparse or moderate obstacles, regardless of using faster or slower soil preparation methods or seedling reloading systems. However, on obstacle-rich terrain, three-headed planting devices were more productive than four-headed, while one-headed were as equally productive as twoheaded devices. Obstacle-rich terrain sometimes inhibited those large four-headed devices from planting even one seedling at a given machine stationary point. Therefore, we conclude that three planting heads per cranemounted device seems to be the most realistic configuration for combining high productivity with good silvicultural results on all the terrain types that a planting machine might work on in Fennoscandia. Future studies should investigate the silvicultural effects of different tree spacing geometries and the corresponding suitable geometrical design of three-headed crane-mounted planting devices