A comprehensive resilience assessment of Mexican tree species and their relationship with drought events over the last century

Abstract

The resilience of forests to drought events has become a major natural resource sustainability concern, especially in response to climate change. Yet, little is known about the legacy effects of repeated droughts, and tree species ability to respond across environmental gradients. In this study, we used a tree‐ring database (121 sites) to evaluate the overall resilience of tree species to drought events in the last century. We investigated how climate and geography affected the response at the species level. We evaluated temporal trends of resilience using a predictive mixed linear modeling approach. We found that pointer years (e.g., tree growth reduction) occurred during 11.3% of the 20th century, with an average decrease in tree growth of 66% compared to the previous period. The occurrence of pointer years was associated with negative values of the Standardized Precipitation Index (SPI, 81.6%) and Palmer Drought Severity Index (PDSI, 77.3%). Tree species differed in their resilience capacity, however, species inhabiting xeric conditions were less resistant but with higher recovery rates (e.g., Abies concolor, Pinus lambertiana, and Pinus jeffreyi). On average, tree species needed 2.7 years to recover from drought events, with extreme cases requiring more than a decade to reach pre‐drought tree growth rates. The main abiotic factor related to resilience was precipitation, confirming that some tree species are better adapted to resist the effects of droughts. We found a temporal variation for all tree resilience indices (scaled to 100), with a decreasing resistance (−0.56 by decade) and resilience (−0.22 by decade), but with a higher recovery (+1.72 by decade) and relative resilience rate (+0.33 by decade). Our results emphasize the importance of time series of forest resilience, particularly by distinguishing the species‐level response in the context of legacy of droughts, which are likely to become more frequent and intense under a changing climate.

Short-Term Tree-Ring Series of Pinus hartwegii Lindl. Taken at Ground Level Correlate to Normalized Difference Vegetation Index Series

“…Despite the low inter-correlations at most sites, for both mountains, a slight increase in radial growth is observed around 2017, but this episode of good growth has decreased considerably by the year 2021. It is noticeable that, from 1985 to date, neither mountain has returned to growth levels close to the historical mean corresponding to the value of 1.0 in Figure 2, which could be evidence of the recent loss of forest resilience indicated by other authors [6].…”

“…One strategy to investigate how tree growth is influenced by recent climate variation is to correlate tree-ring width measurements with remotely sensed data. Recently, dendrochronological methods have been used to explain the response of forests to climate change and whether their resistance and resilience are changing [6][7][8]. The historical information recorded in tree rings helps us to understand other changes occurring in the ecosystem, such as droughts [9].…”

Tree Rings as Proxies of Historical Runoff in a National Park in Northern Mexico: A Major Ecosystem Service Provider

“…Before this period, historical archives documented the presence of severe droughts in the 1810s, 1790s, 1770s, 1750s, and 1720s [2]. Dendroclimatic reconstructions also detect intense droughts in previous periods such as the 1670s, 1570s, and 1490s [12][13][14], with severe impacts on forest ecosystems [15].…”

Impacto de Ips confusus Wood & Bright, 1992 en el incremento radial de Pinus cembroides Zucc.

“…Asimismo, una de las principales plagas de pinos son los descortezadores del género Ips, dentro del cual algunas especies que generalmente se consideran plagas secundarias, en ocasiones se comportan como primarias debido, fundamentalmente, al efecto del cambio climático. Es probable que esto se relacione con el estrés al que son sometidos los ecosistemas forestales por el efecto de eventos hidrometeorológicos más extremos y, por lo tanto, una disminución de su resiliencia, lo cual favorece el ataque de plagas (Hernández, 2010;Correa-Díaz et al, 2023).…”

“…Además, si se parte de que el efecto de I. confusus está asociado con la presencia de sequías, la señal climática, especialmente la relacionada con índices de sequía contenida en los anillos de crecimiento de AA, debería ser mayor. Dado que se ha descrito la disminución de la resiliencia de los bosques por el efecto de sequías (Correa-Díaz et al, 2023), la información de esta investigación será útil para realizar recomendaciones de manejo forestal posterior a un evento de intensa sequía, y minimizar el daño que se ocasione, en particular, las infestaciones y mortandad del arbolado.…”