cross-posted from: https://sopuli.xyz/post/44290823
Fig. 1. a) Historical hurricane tracks that came within our search range (250 km of New York City: dashed circle). The categories shown are based on the Saffir-Simpson Hurricane Wind Scale (Saffir, 1973, Simpson, 1974). Storm track color denotes hurricane category at a given location (see key). b) Inset showing tree-ring site locations for 1. Montauk, New York, 2. Mashomack, New York, and 3. Newport, Rhode Island. c) The scanned sample image (top) compared to the image that was produced using quantitative wood anatomy methods (bottom). d) Close up of cell detail for 1977 and 1978 with inset highlighting vessel tylosis and detail on earlywood and latewood separation within a growth ring. The base map for panel (a) and (b) was produced on NOAA’s Historical Hurricane Track interactive mapper: https://coast.noaa.gov/digitalcoast/tools/hurricanes.html
Fig. 2. Left: Residual (RES) tree-ring width chronologies from Montauk, New York (panel a), Newport, Rhode Island (panel b), and Mashomack, New York (panel c). Dashed vertical lines denote years of the most significant hurricane events around New York City (i.e., Category 2 or higher within the search radius). Right: Superposed Epoch Analysis showing the response of the normalized tree-ring width chronologies to the hurricane events, with colored uncertainty envelopes surrounding the black line representing the 5th and 95th percentiles of the growth response. The dashed and dotted lines refer to the 5th/95th and 1st/99th significance thresholds, respectively, using a random bootstrapping approach.
…
Importantly, the coastal oak chronologies do not show a strong climate signal from 1902 to 1999, except for Mashomack with a weakly significant and positive current-year signal with May/June precipitation (r = 0.26/0.26; p < 0.05) and SPEI-1 (r = 0.22/0.24, respectively; p < 0.05) (Fig. S2). Montauk shows a weakly positive correlation with previous year November/December precipitation (r = 0.23/0.22; p < 0.05) and November SPEI-1 (0.24; p < 0.05). Newport has weakly negative correlations with prior-year September precipitation (r = -0.27, p < 0.05) and SPEI-1 (r = -0.34, p < 0.05).
This is in contrast to inland tree-ring studies within the region that show stronger sensitivity to summer precipitation or drought variability (Levesque et al., 2017; Pederson et al., 2013). While the sheltered nature of Mashomack may provide an environmental niche more similar to inland forests allowing for the emergence of a weak summer climate signal, Montauk and Newport, seem to be insensitive to summer climate variability. Overall, although there were some significant correlations (p < 0.05) between climate variability from individual months and RW variability, correlations were weak (r < 0.3), some occurring in the previous year (t-1), and there were no notable correlation commonalities shared by the sites.
Our results fall in line with prior research in the region indicating that regional-scale climate variability is not the strongest limiting factor of radial growth of coastal trees. Rather, other environmental factors and ocean effects (Pearl et al., 2020; Tucker and Pearl, 2021) may play a more important role in their year-to-year radial growth. These trees are growing in a highly disturbance-prone region, very close to the sea, and subject to strong winds and salt spray. Paleotempestological tree-ring studies from more climate sensitive regions had success isolating a hurricane signature after removing the climate signal from the tree-ring data (Collins-Key and Altman, 2021). This filtering was not necessary here given the lack of strong climate signals across the sites.
…
Our study demonstrates that ring-width records from oak trees (Quercus spp.) growing at several coastal sites in New York and Rhode Island, and one beech site (Fagus grandifolia) from Massachusetts, capture major historical hurricane events over the 19th and 20th centuries. This is manifested by severely reduced ring width and latewood width, and for the Montauk site, relatively high lumen area ratio values in the year following the storm. In combination, this multi-parameter approach could help us better pin-point hurricane events prior to the observational record, particularly the strongest storms–Category 3 and larger in the tree-ring record.
Our results also show that wood anatomy from white oak (Quercus alba) from coastal forests, has strong potential in terms of hurricane detection, providing a critical first step in developing a protocol for analyzing these forests. Future studies could benefit from additional parameters (e.g., stable isotopes, additional anatomical traits), and/or other paleotempestological proxies (e.g., sediment cores), to develop a better understanding of historical hurricane activity across the northeastern United States.
Our findings also indicate that these forests demonstrate a remarkable capacity for recovery following large-scale disturbances, such as hurricanes. Unlike studies of conifers (Tucker et al., 2018; Fernandes et al., 2018), we found that oak and beech trees from Montauk, Newport, and Naushon Island sites had fully regained their radial growth by the second growing season after a hurricane, with trees at Mashomack only slightly lagging this rapid recovery. This suggests a high tolerance to disturbance for oaks (4 sites) and beech (1 site). Future investigations require more sites from a variety of tree species to elucidate differences in hurricane response depending on forest types (e.g. conifers vs angiosperms).
Despite the resilience of coastal forests to hurricane impacts, these forests are increasingly at risk from storm damage and surges, and continued sea-level rise. We would expect that compound events and stressors, such as sea-level rise, storm surges, and physical damage from hurricanes, could further alter site conditions beyond the thresholds these ecosystems can tolerate. Our results show that forest growth is already negatively correlated with sea-level height anomalies. Given the critical role these forests play in the sustainability of densely populated communities—by buffering wind, supporting dune infrastructure, enhancing groundwater recharge, and sustaining wildlife—greater attention is needed to study and protect remaining coastal forests.
link to open access article…
https://www.sciencedirect.com/science/article/pii/S092181812600144X
