Growth of 19 conifer species is highly sensitive to winter warming, spring frost and summer drought

Abstract

Background and Aims Conifers are key components of many temperate and boreal forests and are important for forestry, but species differences in stem growth responses to climate are still poorly understood and may hinder effective management of these forests in a warmer and drier future. Methods We studied 19 Northern Hemisphere conifer species planted in a 50-year-old common garden experiment in the Netherlands to 1) assess the effect of temporal dynamics in climate on stem growth; 2) test for a possible positive relationship between the growth potential and climatic growth sensitivity across species, and 3) evaluate to what extent stem growth is controlled by phylogeny. Key results Eighty-nine percent of the species showed a significant reduction in stem growth to summer drought, 37% responded negatively to spring frost, 32% responded positively to higher winter temperatures. Species differed largely in their growth sensitivity to climatic variation and showed for example, a 4-fold difference in growth reduction to summer drought. Remarkably, we did not find a positive relationship between productivity and climatic sensitivity, but instead observed that some species combined a low growth sensitivity to summer drought with high growth potential. Both growth sensitivity to climate and growth potential were partly phylogenetically controlled. Conclusions A warmer and drier future climate is likely to reduce the productivity of most conifer species. We did not find a relationship between growth potential and growth sensitivity to climate; instead, some species combined high growth potential with low sensitivity to summer drought. This may help forest managers to select productive species that are able to cope with a warmer and drier future.

Drought resilience of conifer species is driven by leaf lifespan but not by hydraulic traits

“…Juniperus species) (Table S1). To quantify the inherent growth rate of species, three different dimensions of growth rate were obtained from Song et al (2021): stem diameter growth rate (cm yr À1 ), stem basal area growth rate (BAI, cm 2 yr À1 ) based on the averaged basal area increment, and stem mass growth rate (kg yr À1 m À1 ) calculated based on wood density and stem area growth (Sterck et al, 2012). These growth rates were calculated based on the first 20 yr since tree species were established, the canopy was perhaps relatively open and there was less competition among individuals (see methods described by Song et al, 2021).…”

Regrowth Response and Nutritional Composition of Moringa oleifera to Cutting Back in Three Agro-Ecological Zones in South Africa

“…Moringa oleifera can adapt to low temperatures, but temperatures below −5 • C, even for one night, can significantly affect the tree [29]. For many reasons, frost can negatively affect plants, resulting in freezing-induced cavitation [30], as an example.…”

“…The re-sprouting rate of M. oleifera trees was highly influenced by the prevailing ambient temperatures, with minimum daily temperatures being the primary factor affecting the productivity of the crop. Moringa oleifera is a drought-tolerant crop that tolerates annual rainfall from 250 to 3000 mm/annum, with optimum ambient temperatures fluctuating between 25 and 35 • C. The tree grows well in warm, semi-arid tropical conditions [29].…”

Growth resilience of conifer species decreases with early, long‐lasting and intense droughts but cannot be explained by hydraulic traits

“…P50) was obtained from the vulnerable curves. For detailed measurement of cavitation resistance and hydraulic conductivity, see Song, Sass‐Klaassen, et al (2021). Finally, the hydraulic safety margin (HSM) on species level was calculated as the difference between Ψmin and P50.…”