We present the first network of tree-ring chronologies for co-occurring Nothofagus nervosa and Nothofagus obliqua in Argentina. Using standard dendrochronological techniques, we developed seven tree-ring width chronologies for each species, encompassing their E-W distribution along a precipitation gradient. Chronology statistics indicated that N. nervosa and N. obliqua are strong candidates for research in dendrochronology. The chronologies were used to study and compare the temporal and spatial growth patterns of each species. Correlation and principal components analysis of the tree-ring chronologies serve as evidence of a strong common signal, indicating shared regional growth patterns across the gradient with some exceptions between sites and species. These results indicate the high potential of N. nervosa and N. obliqua for their use in dendroclimatology.

The North American Dendroecological Field week (NADEF) is an intensive dendrochronology workshop, funded in part by the National Science Foundation. The 2019 Introductory Group at NADEF developed two precisely dated tree-ring width chronologies for Pinus contorta (lodgepole pine) and Pinus flexilis (limber pine) at the Wolf Knob site ca. 5 km west of Beartooth Lake, WY, within the bounds of the Shoshone National Forest (SNF), in the Greater Yellowstone Ecosystem (GYE). Wolf Knob is a semi-arid, S- to SW-facing, mid- to high-elevation site, making it an ideal location to examine the climate sensitivity of annual tree-ring width increments. Here, we show that two co-located Pinus species exhibit differing climate–growth relationships, with P. contorta exhibiting relatively weak correlations with precipitation (r = 0.37; p < 0.01) and temperature (r = –0.23; p < 0.05) during the late summer, and P. flexilis exhibiting stronger overall correlations with both cool-season (r = 0.48; p < 0.01) and warm-season precipitation (r = 0.51; p < 0.01) as well as with snowpack records (r = 0.45; p < 0.05). Our results suggest these two Pinus species may face disparate threats in the face of regional climate change, with P. flexilis being particularly vulnerable to drought conditions and declining snowpacks in the GYE. The differing seasonal climate sensitivities of the two species is likely caused by microsite conditions (e.g. soil moisture capacity, incoming solar radiation) and distinct species-climate responses, underscoring the importance of not only site selection, but also microsite and individual selection in dendroclimatological sampling. Finally, this work contributes to identifying Snow Water Equivalent (SWE)-sensitive tree-ring proxies in the GYE, critical for understanding ongoing warming-induced snowpack declines across western North America, particularly given the projections of a largely snow-free (April 1) GYE by 2075.

Forest management constantly seeks tools that can optimize the production of goods and services. As natural archives, tree rings have proven to be effective in terms of refining the dynamics of growth on a temporal basis. This study evaluates the application of these tree rings in estimating the effect of pith eccentricity on forest growth, modeling the increase in basal area (BAI) and identifying disturbances in five coexisting species in northern Mexico. A Wilcoxon rank sum test showed significant differences, with higher radial growth in the north direction compared to the other directions. A mixed model analysis revealed two patterns of BAI growth, fast and slow growing. The former includes P. arizonica, P. engelmannii and P. leiophylla, whereas the latter comprises P. durangensis and P. lumholtzii. The fast-growing group shows a higher increment during the sapling stage. However, during subsequent stages, it presents growth rates similar to those of the slow-growing group. Finally, the percentage growth change (PGC) filter approach identified species disturbances with differential species responses, which temporarily cause uneven-aged forest. We conclude that tree rings can provide valuable information for forest management, and their temporal amplitude can be supported with information from permanent plots.

Modification of forest trees can occur from a variety of factors. Both cultural and natural processes can injure trees and many injuries can be dated dendrochronologically. Distinguishing between types of injuries, however, is important for understanding past human land-use practices and delineating different activities or processes that impact the forest. In the Zuni Mountains of New Mexico, USA, we have identified trees intentionally peeled for their cambial layer and unintentionally damaged trees whose scars resemble cambium-peeled trees. Both detailed attribute recording and dendrochronological dating were used to identify past exploitation of this ponderosa pine forest.

The Cumberland Homesteads Historic District, located on the Cumberland Plateau in East Tennessee, is home to one of the first and largest Homesteads projects attempted during the New Deal era. Although the settlement did not succeed in its original objective, the history of the Cumberland Homesteads has become a valued foundation of the local community, which in turn strives to protect the legacy of the Cumberland Homesteads Tower. To preserve the integrity of the structure as well as the historical integrity of the landscape, the Cumberland Homesteads Tower Association sought to date and potentially remove trees that were not present during the period of significance (prior to 1938). The majority of the trees in close proximity to the Tower were identified as Eastern hemlock (Tsuga canadensis (L.) Carrière) and 15 trees total were sampled. Additionally, three post oak (Quercus stellata Wangenh.) trees located in a historic ‘triangle’ across the highway from the Tower and targeted for removal were sampled. Samples were successfully dated, and ca. half of the hemlock were confirmed to have been planted after the construction of the Homesteads Tower. Additionally, post oaks analyzed near the Tower were dated back to the early 1800s, which motivated their protection in the midst of a road project threatening their survival.

Dendrochronological research in NW Spain is aimed at developing reference chronologies of oak (Quercus sp.), which are suitable for absolute age determinations of cultural heritage from the Basque Country. So far, the main research interest has been on rural architecture such as farmhouses and barns. In order to extend the application range of Basque dendrochronology, the current study focuses on tree-ring research of rural furniture. In close consultation with the curators of cultural centre Gordailu (Irun), four granary chests and a wardrobe were selected for this pilot study. The tree-ring patterns of these objects significantly match against the new Basque reference chronologies, yielding absolute calendar years for the studied panels. The last-formed measured ring from the oldest granary chest in this collection dates to AD 1517. The other three chests have last-formed rings dating to AD 1580, 1665 and 1829, and the wardrobe has a last-formed ring dating to AD 1439. Sapwood ring counts from living oaks in this region were used to estimate the number of sapwood rings missing on the outside of the panels. Derived absolute and terminus post quem felling dates of wood were further refined by adding the estimated drying time of the wood based on information derived from traditional carpenters in this area. All dendrochronologically established construction dates constitute a correction or refinement of the original art-historical age determinations. In addition, the previously assigned provenance of one granary chest could be corrected. These results indicate that dendrochronology is an excellent method to refine our knowledge about the age, and in some cases the exact geographical provenance, of rural movable heritage in and from the Basque region. The fact that the previously established provenance of four of the studied objects within the Basque Country could not be refined further implies that most Basque reference chronologies at present are not sufficiently specific for assessing wood provenance on an intra-regional scale. This can be solved in the future by reassembling the data underlying these chronologies into homogeneous timber groups covering smaller, ecologically more similar, geographical growth areas.