scholarly journals Forest Stand Species Mapping Using the Sentinel-2 Time Series

2019 ◽  
Vol 11 (10) ◽  
pp. 1197 ◽  
Author(s):  
Ewa Grabska ◽  
Patrick Hostert ◽  
Dirk Pflugmacher ◽  
Katarzyna Ostapowicz
Keyword(s):  
Time Series ◽  
Tree Species ◽  
Forest Tree ◽  
Species Discrimination ◽  
Accurate Information ◽  
Silver Fir ◽  
Forest Tree Species ◽  
Wide Range ◽  
Species Mapping ◽  
Sentinel 2

Accurate information regarding forest tree species composition is useful for a wide range of applications, both for forest management and scientific research. Remote sensing is an efficient tool for collecting spatially explicit information on forest attributes. With the launch of the Sentinel-2 mission, new opportunities have arisen for mapping tree species owing to its spatial, spectral, and temporal resolution. The short revisit cycle (five days) is crucial in vegetation mapping because of the reflectance changes caused by phenological phases. In our study, we evaluated the utility of the Sentinel-2 time series for mapping tree species in the complex, mixed forests of the Polish Carpathian Mountains. We mapped the following nine tree species: common beech, silver birch, common hornbeam, silver fir, sycamore maple, European larch, grey alder, Scots pine, and Norway spruce. We used the Sentinel-2 time series from 2018, with 18 images included in the study. Different combinations of Sentinel-2 imagery were selected based on mean decrease accuracy (MDA) and mean decrease Gini (MDG) measures, in addition to temporal phonological pattern analysis. Tree species discrimination was performed using the Random Forest classification algorithm. Our results showed that the use of the Sentinel-2 time series instead of single date imagery significantly improved forest tree species mapping, by approximately 5–10% of overall accuracy. In particular, combining images from spring and autumn resulted in better species discrimination.

Mapping temperate forest tree species using dense Sentinel-2 time series

2021 ◽  
Vol 267 ◽  
pp. 112743
Author(s):  
Jan Hemmerling ◽  
Dirk Pflugmacher ◽  
Patrick Hostert
Keyword(s):  
Time Series ◽  
Tree Species ◽  
Temperate Forest ◽  
Forest Tree ◽  
Forest Tree Species ◽  
Sentinel 2

scholarly journals Muster und treibende Kräfte der Samenproduktion bei Waldbäumen

2016 ◽  
Vol 167 (6) ◽  
pp. 316-324 ◽  
Author(s):  
Thomas Wohlgemuth ◽  
Anita Nussbaumer ◽  
Anton Burkart ◽  
Martin Moritzi ◽  
Ulrich Wasem ◽  
...  
Keyword(s):  
Tree Species ◽  
Driving Forces ◽  
Abies Alba ◽  
Forest Tree ◽  
Fruit Production ◽  
Mast Seeding ◽  
Silver Fir ◽  
Fine Scale ◽  
Central Plateau ◽  
Forest Tree Species

Patterns and driving forces for seed production in forest tree species Why is the annual fruit production in forest tree species not constant, and which factors cause massive fruit production (seed mast year)? These and other related questions were already posed more than 100 years ago when tree breeding was economically beneficial. The questions have not been fully answered, yet. Rather, the same questions are studied again today as the climate is changing and the uncertainty about the continuation of forests at their current locations is growing. A 25 year long observation series on the variation of fruit production in Switzerland revealed a mean frequency of three years for mast seeding (full and medium mast) at low elevation on the Central Plateau in European beech (Fagus sylvatica), oak (Quercus petraea, Q. robur) and silver fir (Abies alba). In contrast, mast seed years of Norway spruce (Picea abies) occurred, on average, every sixth year. In 1992 and 2011, all four species synchronously showed mast seeding. The results are discussed in the light of different theories and new research findings. From the state of the current know ledge, we derive the need for long-term and fine-scale baseline data and present the new reporting and information webpage «mast web.ch». Here, volunteers can report observations on the fruit production of main tree species following a few simple criteria (citizen science approach). With this data, distribution maps on mass fructification levels will be made available and will serve for spatio-temporal fine-scale studies on mast seeding phenomena.

scholarly journals Botryosphaeriaceae Species Associated With Cankers and Dieback Symptoms of Acacia mangium and Pinus caribaea var. hondurensis in Venezuela

Plant Disease ◽  
2016 ◽  
Vol 100 (12) ◽  
pp. 2455-2464 ◽  
Author(s):  
J. R. Úrbez-Torres ◽  
F. Castro-Medina ◽  
S. R. Mohali ◽  
W. D. Gubler
Keyword(s):  
Dna Sequences ◽  
Tree Species ◽  
Phylogenetic Analyses ◽  
Elongation Factor ◽  
Acacia Mangium ◽  
Forest Tree ◽  
Pinus Caribaea ◽  
Internal Transcribed Spacer Region ◽  
Forest Tree Species ◽  
Wide Range

Several species in the Botryosphaeriaceae family cause wood stain, cankers, and dieback of trunks and branches in a wide range of forest tree species. The aim of this study was to characterize the botryosphaeriaceous fungi associated with decline symptoms observed in Acacia mangium and Pinus caribaea var. hondurensis, two economically important forest tree species grown in commercial plantations in Venezuela. Fungi isolated from symptomatic samples collected from both hosts in commercial sites were identified based on their morphology and DNA sequences of the internal transcribed spacer region (ITS1-5.8S-ITS2) and part of the β-tubulin and translation elongation factor 1-α genes. Lasiodiplodia theobromae and L. venezuelensis were routinely isolated from A. mangium and P. caribaea var. hondurensis. Additionally, the novel species Diplodia guayanensis was isolated and characterized from symptomatic and asymptomatic tissues of A. mangium. Multigene phylogenetic analyses along with restriction fragment length polymorphism studies further supported the identification of these species. A pathogenicity study was conducted under natural conditions and 12 weeks after inoculation all Botryosphaeriaceae spp. were shown to be highly virulent on A. mangium. Contrary, no lesions were observed in the wood of P. caribaea var. hondurensis when inoculated with L. theobromae and L. venezuelensis. However, both species were consistently reisolated from the asymptomatic tissue beyond the inoculation point. This study contributes to a better understand the role that species in the Botryosphaeriaceae play on disease symptoms and dieback of A. mangium and P. caribaea var. hondurensis from plantations in eastern Venezuela.

scholarly journals How Spatial Resolution Affects Forest Phenology and Tree-Species Classification Based on Satellite and Up-Scaled Time-Series Images

2021 ◽  
Vol 13 (14) ◽  
pp. 2716
Author(s):  
Kaijian Xu ◽  
Zhaoying Zhang ◽  
Wanwan Yu ◽  
Ping Zhao ◽  
Jibo Yue ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Time Series ◽  
Spatial Resolution ◽  
Tree Species ◽  
Deciduous Forest ◽  
Forest Tree ◽  
Image Resolution ◽  
Species Classification ◽  
Forest Tree Species ◽  
Time Series Images

The distribution of forest tree species provides crucial data for regional forest management and ecological research. Although medium-high spatial resolution remote sensing images are widely used for dynamic monitoring of forest vegetation phenology and species identification, the use of multiresolution images for similar applications remains highly uncertain. Moreover, it is necessary to explore to what extent spectral variation is responsible for the discrepancies in the estimation of forest phenology and classification of various tree species when using up-scaled images. To clarify this situation, we studied the forest area in Harqin Banner in northeast China by using year-round multiple-resolution time-series images (at four spatial resolutions: 4, 10, 16, and 30 m) and eight phenological metrics of four deciduous forest tree species in 2018, to explore potential impacts of relevant results caused by various resolutions. We also investigated the effect of using up-scaled time-series images by comparing the corresponding results that use pixel-aggregation algorithms with the four spatial resolutions. The results indicate that both phenology and classification accuracy of the dominant forest tree species are markedly affected by the spatial resolution of time-series remote sensing data (p < 0.05): the spring phenology of four deciduous forest tree species first rises and then falls as the image resolution varies from 4 to 30 m; similarly, the accuracy of tree species classification increases as the image resolution varies from 4 to 10 m, and then decreases as the image resolution gradually falls to 30 m (p < 0.05). Therefore, there remains a profound discrepancy between the results obtained by up-scaled and actual remote sensing data at the given spatial resolutions (p < 0.05). The results also suggest that combining phenological metrics and time-series NDVI data can be applied to identify the regional dominant tree species across different spatial resolutions, which would help advance the use of multiscale time-series satellite data for forest resource management.

A case of gender equality: absence of sex-related costs in a dioecious tropical forest tree species

Plant Ecology ◽  
2021 ◽  
Author(s):  
Valéria Forni Martins ◽  
Rafaela Letícia Brito Bispo ◽  
Priscilla de Paula Loiola
Keyword(s):  
Tropical Forest ◽  
Gender Equality ◽  
Tree Species ◽  
Forest Tree ◽  
Forest Tree Species

scholarly journals Fire suppression and seed dispersal play critical roles in the establishment of tropical forest tree species in southeastern Africa

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tomohiro Fujita
Keyword(s):  
Seed Dispersal ◽  
Tree Species ◽  
Seedling Survival ◽  
Fire Suppression ◽  
Forest Tree ◽  
Tree Seedlings ◽  
Seedling Mortality ◽  
Forest Tree Species ◽  
Seed Deposition ◽  
Syzygium Guineense

AbstractThis study examined the mechanisms of facilitation and importance of seed dispersal during establishment of forest tree species in an Afrotropical woodland. Seedling survival of Syzygium guineense ssp. afromontanum was monitored for 2.5 years at four different microsites in savannah woodland in Malawi (southeastern Africa) under Ficus natalensis (a potential nurse plant), Brachystegia floribunda (a woodland tree), Uapaca kirkiana (a woodland tree), and at a treeless site. The number of naturally established forest tree seedlings in the woodland was also counted. Additionally, S. guineense ssp. afromontanum seed deposition was monitored at the four microsites. Insect damage (9% of the total cause of mortality) and trampling by ungulates (1%) had limited impact on seedling survival in this area. Fire (43%) was found to be the most important cause of seedling mortality and fire induced mortality was especially high under U. kirkiana (74%) and at treeless site (51%). The rate was comparatively low under F. natalensis (4%) and B. floribunda (23%), where fire is thought to be inhibited due to the lack of light-demanding C4 grasses. Consequently, seedling survival under F. natalensis and B. floribunda was higher compared with the other two microsites. The seedling survival rate was similar under F. natalensis (57%) and B. floribunda (59%). However, only a few S. guineense ssp. afromontanum seedlings naturally established under B. floribunda (25/285) whereas many seedlings established under F. natalensis (146/285). These findings indicate that the facilitative mechanism of fire suppression is not the only factor affecting establishment. The seed deposition investigation revealed that most of the seeds (85%) were deposited under F. natalensis. As such, these findings suggest that in addition to fire suppression, dispersal limitations also play a role in forest-savannah dynamics in this region, especially at the community level.

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