No abstract

Longleaf pine (Pinus palustris Mill.) forests are an important ecosystem in the southeastern United States, with high economic and ecological value. It is necessary to study the climate variation within its range in order to understand the effects of climate change on longleaf pine forests. In this study, past climate data at three sites within the longleaf pine range were used to detect climate variation. The results indicated no dramatic change in solar radiation at the three sites. There were high variations in annual air temperature at the three sites. The trend of annual air temperature change depended on the time scale and start/end time. The annual air temperature generally increased from the 1960s at three sites. However, from 1901 to 2020, the trend of increasing annual air temperature was not consistent. The annual precipitation and the standardized precipitation-evapotranspiration index were relatively stable, with variation at the three sites. The regimes of annual and monthly air temperature and precipitation were not shifted based on the analysis of multiscale entropy. The climate niche of longleaf pine forests based on long-term climate data was broader than previously found. These results may be helpful to understand the interactions of the atmosphere and growth of longleaf pine forest and develop relevant management strategies.

Climate change poses many risks to economically and ecologically crucial species. Longleaf pine (Pinus palustris Mill.) trees are keystone species that were once dominant across the southeastern United States, but now occupy less than 5% of their historic range and are thus classified as endangered. Here we review the current status and challenges facing longleaf pine trees, what is known on how changing climate will impact longleaf growth and reproduction, and gaps in the literature that are important to address. We found that many fundamental aspects of longleaf pine growth and reproduction are understood. However, these systems are complex, and not all is known about each factor that influences the relationship between climate, growth, and reproductive output. Additionally, long-term data sets capable of examining all relevant factors in these relationships do not currently exist. To fill necessary gaps, we recommend a joint approach between using readily available data sets and establishing new long-term monitoring plots targeted to collect data on missing or poorly understood conditions. This review provides a clue from an ecological complexity perspective to understand and manage longleaf pine forests under climate change.

No abstract

Plants automatically control the size variations in organs to achieve efficient exploitation of resources. However, it is unclear whether the scaling relationships of plant organs share a similar character for different individuals under varied micro-conditions (e.g., light and soil water). We conducted a case study of the lengths of staghorn sumac leaves and longleaf pine cone scales to test the relationships. Our results indicated that although there were size variations, there existed power laws of frequency in the lengths of staghorn sumac leaves and longleaf pine cone scales. The exponents differed but were positively correlated with the minimum length of leaves or cone scales. Taylor’s Law existed in the lengths of cone scales and some tree leaves, and scale break was observed. This study provides new information on scaling relationships and self-organization in the patterns of tree parts arrangement. Taylor’s Law may be used to detect minor changes in the growth regime.