Optimizing the airborne laser scanning estimation of basal area larger than mean (BALM): An indicator of cohort balance in forests

Airborne laser scanning (ALS) assisted basal area larger than mean (BALM) estimation measures the cohort balance in forests and provides adequate opportunities to describe forest structure. However, a problem still exists that how the plot size, sample size (number of trees), and ALS point density affect the BALM estimation. We tackled this question by using both field and ALS data from a typical managed boreal forest area in Finland. Various concentric circular plots (1-15 m radii) were simulated within the actual field plots (squared) and the optimal plot size and sample size were selected by observing changes in the absolute correlation between BALM estimates and various ALS metrics. Instability in the correlation was found at the smaller concentric circular plots (1-5 m radii) and sample sizes (less than 6 trees) but as the plot size and sample size increased, the correlation followed a convex curve. The maximum correlation was found between a concentric circular plot size 11-14 m radii (380-615 m2 area) and sample size 50-80 trees which could be the optimal plot size and sample size for a reliable BALM estimation. With regards to the ALS point density, no major effects were observed on the relationship between BALM estimates and various ALS metrics unless the point density is less than at least 5 points m 2. The point density of the current nationwide ALS survey is matching the minimum point density requirement obtained in this study and thus it is suitable for a reliable forest structural assessment

Taimiuutiset 2/2016

4 Tutkimusta tulevaisuuden istutusketjuista 6 Kuusi valtaa alaa 10 Voiko laserkeilauksella löytää hirvituhoalueita? 13 Kuusen solukkolisäyksen tutkimus jatkuu Lukessa 17 Kuusen ja männyn taimien kasvua ja rakennetta voi ohjata erilaisilla valon spektreillä 21 Taimien talveentumiskehitys tulevaisuuden ilmasto-olosuhteissa: Erilaisia reaktioita eri puulajeilla ja alkuperillä 23 Peittoaineiden vaikutus kasvualaustan vesipitoisuuteen ja kuusen taimien kasvuun 26 Hallakastelun käyttö pakkasvaurioiden estämiseen 29 Siemenlevintäinen Diplodia pinea -sien havaittu ensi kertaa Suomessa 31 Erinomainen kirja kasvihuoneviljelystä 31 Laatua ja monimuotoisuutta metsänuudistamiseen 32 Puupelto-city sarjakuva Listaa artikkelit201

The declining occurrence of moose (Alces alces) at the southernmost edge of its range raise conservation concerns

The border region between Austria, the Czech Republic, and Germany harbors the most south-western occurrence of moose in continental Europe. The population originated in Poland, where moose survived, immigrated from former Soviet Union or were reintroduced after the Second World War expanded west and southwards. In recent years, the distribution of the nonetheless small Central European population seems to have declined, necessitating an evaluation of its current status. In this study, existing datasets of moose observations from 1958 to 2019 collected in the three countries were combined to create a database totaling 771 records (observations and deaths). The database was then used to analyze the following: (a) changes in moose distribution, (b) the most important mortality factors, and (c) the availability of suitable habitat as determined using a maximum entropy approach. The results showed a progressive increase in the number of moose observations after 1958, with peaks in the 1990s and around 2010, followed by a relatively steep drop after 2013. Mortality within the moose population was mostly due to human interactions, including 13 deadly wildlife-vehicle collisions, particularly on minor roads, and four animals that were either legally culled or poached. Our habitat model suggested that higher altitudes (ca. 700–1,000 m a.s.l.), especially those offering wetlands, broad- leaved forests and natural grasslands, are the preferred habitats of moose whereas steep slopes and areas of human activity are avoided. The habitat model also revealed the availability of large core areas of suitable habitat beyond the current distribution, suggesting that habitat was not the limiting factor explaining the moose distribution in the study area. Our findings call for immediate transboundary conservation measures to sustain the moose population, such as those aimed at preventing wildlife-vehicle collisions and illegal killings. Infrastructure planning and development activities must take into account the habitat requirements of moose.publishedVersio

Airborne lidar for woodland habitat quality monitoring: exploring the significance of lidar data characteristics when modelling organism-habitat relationships

Structure is a fundamental physical element of habitat, particularly in woodlands, and hence there has been considerable recent uptake of airborne lidar data in forest ecology studies. This paper investigates the significance of lidar data characteristics when modelling organism-habitat relationships, taking a single species case study in a mature woodland ecosystem. We re-investigate work on great tit (Parus major) habitat, focussing on bird breeding data from 1997 and 2001 (years with contrasting weather conditions and a demonstrated relationship between breeding success and forest structure). We use a time series of three lidar data acquisitions across a 12-year period (2000–2012). The lidar data characteristics assessed include time-lag with field data (up to 15 years), spatial sampling density (average post spacing in the range of 1 pulse per 0.14 m2–17.77 m2), approach to processing (raster or point cloud), and the complexity of derived structure metrics (with a total of 33 metrics assessed, each generated separately using all returns and only first returns). Ordinary least squares regression analysis was employed to investigate relationships between great tit mean nestling body mass, calculated per brood, and the various canopy structure measures from all lidar datasets. For the 2001 bird breeding data, the relationship between mean nestling body mass and mean canopy height for a sample area around each nest was robust to the extent that it could be detected strongly and with a high level of statistical significance, with relatively little impact of lidar data characteristics. In 1997, all relationships between lidar structure metrics and mean nestling body mass were weaker than in 2001 and more sensitive to lidar data characteristics, and in almost all cases they were opposite in trend. However, whilst the optimum habitat structure differed between the two study years, the lidar-derived metrics that best characterised this structure were consistent: canopy height percentiles and mean overstorey canopy height (calculated using all returns or only first returns) and the standard deviation of canopy height (calculated using all returns). Overall, our results suggest that for relatively stable woodland habitats, ecologists should not feel prohibited in using lidar data to explore or monitor organism–habitat relationships because of perceived data quality issues, as long as the questions investigated, the scale of analysis, and the interpretation of findings are appropriate for the data available

Predicting the provisioning potential of forest ecosystem services using airborne laser scanning data and forest resource maps

201

Missä hirvet elävät? : Hirvien elinpiirit ja habitaattivalinta Pohjanmaalla

Hirvi on Suomen merkittävin riistaeläin, jonka takia sitä on myös tutkittu paljon. Hirvien vaatimukset habitaattien suhteen vaihtelevat mm. vuodenaikojen mukaan. Tehokkaan hirvikannan hoidon varmistamiseksi on habitaattivalintaa tutkittava eri puolilla Suomea, sillä ympäristöolosuhteet vaihtelevat alueittain suuresti. Tässä tutkimuksessa selvitettiin, kuinka laajoja hirvien kesä- ja talvielinpiirit ovat sekä minkälaisia habitaatteja hirvet suosivat Pohjanmaan alueella kesäisin ja talvisin. Habitaattivalintaa tarkasteltiin kahdella eri tasolla: elinpiirin valintaa maisematasolla sekä habitaattivalintaa elinpiirin sisällä. Aineistona käytettiin 33:n GPS-pannoitetun hirven paikannustietoja vuosien 2009-2011 väliltä. Paikannustiedot projisoitiin monilähde-VMI:n päälle, joka oli uudelleenluokiteltu 15 luokkaan. Tulosten perusteella urosten elinpiirit ovat keskimäärin huomattavasti laajempia kuin naaraiden. Kausien välillä tilastollisesti merkitseviä eroja ei löytynyt. Kesäisin hirvet suosivat elinpiiritasolla sekapuustoisia ja muita taimikoita sekä -nuoria metsiä. Talvisin taas suosittiin mäntyvaltaisia taimikoita ja nuoria metsiä sekä välteltiin peltoja ja muita alueita. Sukupuolittain tarkasteltuna tilastollisesti merkitseviä eroja ei löytynyt. Elinpiirien sisäisellä tasolla hirvet suosivat kesäisin lähes kaikkia sekapuustoisia ja muita metsäluokkia sekä nuoria turvepohjaisia mäntymetsiä ja varttuneita mäntymetsiä. Peltoja, vesistöjä ja muita alueita sen sijaan välteltiin. Talvisin hirvet siirtyivät keskimäärin nuorempiin metsäluokkiin suosien lähes kaikkia taimikoita ja nuoria metsiä. Talvisin kaikkia varttuneita metsiä ja peltoja välteltiin. Naaraat suosivat kesäisin uroksia selkeämmin lähes kaikkia sekapuustoisia ja muita metsäluokkia sekä nuoria turvepohjaisia mäntymetsiä. Molemmat sukupuolet välttelivät peltoja, vesialueita ja muita alueita. Talvisin molemmat sukupuolet suosivat lähes kaikkia taimikoita ja nuoria metsiä. Peltoalueita välteltiin hyvin selkeästi. Useamman habitaattivalinnan valinnan tason käyttäminen on välttämätöntä, jotta saataisiin selville, mitä habitaattiluokkia hirvet todella suosivat tai välttelevät ja kuinka voimakkaasti

Utilisation des aménagements agroforestiers linéaires par les mammifères en milieu agricole intensif

L'intensification agricole entraîne une vaste perte d'habitat et de connectivité du paysage. Les espèces subsistantes dans ces paysages dominés par l'agriculture utilisent souvent des éléments du paysage linéaires et minces, comme des haies brise-vent et des fossés végétalisés, en tant qu’habitat ou comme corridor de déplacement entre les parcelles d’habitat. Toutefois, la compréhension de l’utilisation de ces aménagements agroforestiers linéaires (AAL) par la faune est limitée et pourrait profiter de l’utilisation de données de télédétection à haute résolution, qui sont non biaisées, détaillées et reproductibles. Le but de cette étude est d’évaluer les caractéristiques qui affectent l’utilisation des AAL par les mammifères de moyenne et grande taille, avec des données in situ et de télédétection, dans un paysage dominé par l’agriculture dans le sud du Québec. Vingt-trois AAL ont été sélectionnés et caractérisés, à la fois par des relevés terrain et des analyses de télédétection (entre autres métriques LiDAR et indices de végétation). La fréquentation de chaque AAL par les mammifères a été mesurée à l'aide de pièges photographiques, de la fin du printemps au début de l'automne 2018. Nous avons obtenu 431 détections de mammifères, tous les AAL combinés. Parmi ces détections, sept espèces ont été répertoriées, toutes opportunistes et bien adaptées au milieu agricole. Nos résultats démontrent qu’il y a des différences significatives dans l'utilisation des AAL par les mammifères, liées à l'influence unique de l’assemblage des caractéristiques considérés. Une dizaine de modèles de régression ont été testés et le modèle retenu basé sur l'AICc comprend plusieurs caractéristiques, tant locales que du paysage. Les coefficients de ce modèle indiquent une relation positive entre l’utilisation des AAL par les mammifères et leur longueur, le couvert arborescent et la quantité d’habitat environnant, alors que cette relation est négative avec la largeur et les perturbations anthropiques. Les données dérivées de télédétection ont contribué à ce modèle final, rappelant leur utilité dans les études sur les habitats fauniques. Ces résultats indiquent que de nombreux facteurs semblent influencer l’utilisation des AAL dans le sud du Québec, que ce soit comme corridor ou comme habitat pour les mammifères. Les informations fournies par cette étude ont généré des suggestions pour une gestion favorable des AAL et la conservation de la faune sauvage en milieu agricole.Agricultural intensification causes habitat modification, sometimes leading to habitat loss and subsequent loss of connectivity. Remaining species in these agriculture-dominated landscapes often use hedgerows, such as windbreaks or riparian strips, as movement corridors or even as habitats. However, the understanding of the use of these hedgerows by mammals is limited and could be improved with the use of high-resolution remote sensing data, which are unbiased, detailed and repeatable. The aim of this study was to assess the attributes that affect medium- and large-sized mammals’ use of hedgerows, with in situ and remotely sensed data (including LiDAR and multispectral images) in an agriculture-dominated landscape in southern Québec. Twenty-three hedgerows were selected and characterized with both field surveys and remote sensing analyses, like LiDAR metrics and vegetation indices. Wildlife frequentation of each hedgerow was measured using camera traps, from late spring to early fall in 2018. 431 mammal detections were obtained among all 23 hedgerows. From this, seven species were recorded, all of them opportunistic and well adapted to agricultural environment. Results showed significant differences in mammal use of hedgerows. Coefficients of the better-ranked models based on AICc indicated a positive relationship between hedgerow length and their use by mammals, and a negative relationship with the hedgerow width. Hedgerow use by mammals also increased as tree cover increased, as habitat became more available and as human disturbance decreased. These results characterized for the first time the variables influencing hedgerow use by a broad set of medium- and large-sized mammal species and confirmed their use as both movement corridor and habitat. This study also confirmed the complementary usefulness of variables derived from remote sensing combined with field data. The low explanatory power of variables often cited in the literature (e.g. NDVI, canopy height) also highlights the need to further explore their specific influence on mammals. The information provided by this study supports the beneficial role played by hedgerows for wildlife conservation in intensive agricultural landscapes. Management guidelines are provided as well as future research avenues

Assessing biodiversity using forest structure indicators based on airborne laser scanning data

The role of forests in biodiversity assessment and planning is substantial as these ecosystems support approximately 80% of the world’s terrestrial biodiversity. Forests provide food, shelter, and nesting environments for numerous species, and deliver multiple ecosystem services. It has been widely recognised that forest vegetation structure and its complexity influence local variations in biodiversity. As forests are facing threats globally caused by human activities, there is a need to map the biodiversity of these ecosystems. The main objective of this review was to summarise the use of airborne laser scanning (ALS) data in biodiversity-related assessment of forests. We draw attention to topics related to animal ecology, structural diversity, dead wood, fragmentation and forest habitat classification. After conducting a thorough literature search, we categorised scientific articles based on their topics, which served as the basis for the section division in this paper. The majority of the research was found to be conducted in Europe and North America, only a small fraction of the study areas was located elsewhere. Topics that have received the most attention were related to animal ecology (namely richness and diversity of forest fauna), assessment of dead trees and tree species diversity measures. Not all studies used ALS data only, as it were often fused with other remote sensing data – especially with aerial or satellite images. The fusion of spectral information from optical images and the structural information provided by ALS was highly advantageous in studies where tree species were considered. Relevant ALS variables were found to be case-specific, so variables varied widely between forest biodiversity studies. We found that there was a lack of research in geographical areas and forest types other than temperate and boreal forests. Also, topics that considered functional diversity, community composition and the effect of spatial resolution at which ALS data and field information are linked, were covered to much lesser extent