Διαδικτυακή Πύλη Συνεργασίας Για Τα Δάση

This report assesses how carbon stocks at regional scales and in individual national forests are affected by factors such as timber harvesting, natural disturbances, climate variability, increasing atmospheric carbon dioxide concentrations, and nitrogen deposition. Previous base­line assessments of carbon stocks (https://www.fs.fed.us/managing-land/sc/carbon) evaluated observed trends based on forest inventory data but were limited in ability to reveal detailed causes of these trends. The expanded assessments reported here are based on an extensive disturbance and climate history for each national forest, and two forest carbon models, to estimate the relative impacts of disturbance (e.g., fires, harvests, insect outbreaks, disease) and nondisturbance factors (climate, carbon dioxide concentration, nitrogen deposition). Results are summarized for each region of the National Forest System in the main document. A set of regional appendices to this report provides more detailed information about individual national forests within each region. Results are highly variable across the United States. Generally, carbon stocks are increasing in forests of the eastern United States as these forests continue to recover and grow older after higher historical harvesting rates and periods of non­forest land use. In contrast, carbon stocks in forests of the western United States may be either increasing or decreasing, depending on recent effects of natural disturbances and climate change. The information supports national forest units in assessing carbon stocks, quantifying carbon outcomes of broad forest management strategies and planning, and meeting carbon assessment requirements of the 2012 Planning Rule and directives. Results of these expanded assessments will provide context for project-level decisions, separated from the effects of factors that are beyond land managers’ control.

Climate change is posing a considerable challenge to foresters. The intensity of required adaptive measures and the relevance of old-growth forests as benchmark for managed forests are debated. Forest managers need to make decisions on stand treatment that are based on climatological and biological parameters with high uncertainties. We provided the conceptual basis for adaptive forest management and provide a number of case studies that reflect the options and limitations of ways of coping with climate change. The examples are derived from the experience of the authors. We conclude that only few forest types are either not strongly affected by climate change or do not require immediate adaptations of forest management. Many productive forests have stand properties that are decisively shaped by past management decisions, such as tree species composition, age distribution, rotation period, and stand structure. Maintaining these properties under the influence of climate change requires continuous and even increasing efforts of forest managers.

Η προσαρμογή της δασικής διαχείρισης προϋποθέτει για τις δασικές υπηρεσίες την απόκτηση νέων γνώσεων και δεξιοτήτων και την αξιοποίησή τους στις πρακτικές που εφαρμόζουν στη διαχείριση των δασών. Υπό το πρίσμα της κλιματικής αλλαγής, κρίνεται αναγκαία η συνέργεια μεταξύ επιστήμης και διαχείρισης στην πράξη, ώστε οι δασικές υπηρεσίες να ανταποκρίνονται σε θέματα όπως η εκτίμηση της τρωτότητας των δασών, ο σχεδιασμός ενδεδειγμένων δασικών διαχειριστικών μέτρων και η εφαρμογή τους, η παρακολούθηση των επιπτώσεων της κλιματικής αλλαγής και των αποτελεσμάτων των μέτρων προσαρμογής στην αλλαγή του κλίματος κ.ά. Η παρούσα έκδοση απευθύνεται στις δασικές υπηρεσίες, και κυρίως στους υπεύθυνους άσκησης δασικής διαχείρισης, στους επαγγελματίες που συμμετέχουν στον σχεδιασμό της δασικής διαχείρισης, στους φοιτητές και σπουδαστές σχετικών τμημάτων εκπαιδευτικών ιδρυμάτων κ.ά., κυρίως σε τοπικό, αλλά και σε περιφερειακό και εθνικό επίπεδο. Ωστόσο, καθώς οι επιπτώσεις της αλλαγής του κλίματος είναι ευρύτερες, για τη διατύπωση προτάσεων προσαρμογής μπορεί να απαιτείται η συμβολή ερευνητών, μη κρατικών οργανώσεων και άλλων εμπλεκομένων. Πολλές από τις επιπτώσεις της αλλαγής του κλίματος (π.χ. πυρκαγιές, επιδημίες παθογόνων οργανισμών), λόγω της φύσης και της έκτασής τους ή θεμάτων δικαιοδοσίας/αρμοδιοτήτων και οικονομικού κόστους, μπορεί να ξεπερνούν τα όρια αρμοδιότητας μίας τοπικής δασικής υπηρεσίας (π.χ. Δασαρχεία), και συνεπώς, σε αυτές τις περιπτώσεις, ενδεχομένως να απαιτείται δράση σε περιφερειακό ή εθνικό επίπεδο.

Forest ecosystems will face direct and indirect impacts from a changing climate over the 21st century. This assessment evaluates the vulnerability of forest ecosystems across the New England region (Connecticut, Maine, Massachusetts, New Hampshire, northern New York, Rhode Island, and Vermont) under a range of future climates. Observed trends in climate over the historical record from 1901 through 2011 show that the mean annual temperature has increased across the region by 2.4 °F, with even greater warming during winter. Precipitation patterns also changed during this time, with a slight trend toward greater annual precipitation and a substantial increase in extreme precipitation events. Projected climate trends using downscaled global climate model data indicate a potential increase in mean annual temperature of 3 to 8 °F for the assessment area by 2100. Projections for precipitation indicate an increase in fall and winter precipitation, and spring and summer precipitation projections vary by scenario. Model projections suggest that many northern and boreal species, including balsam fir, red spruce, and black spruce, may fare worse under future conditions, but other species may benefit from projected changes in climate.