Flammability is an important plant trait, relevant to plant function, wildfire behaviour and plant evolution. However, systematic comparison of plant flammability across ecosystems has proved difficult because of varying methodologies and assessment of different fuels comprising different plant parts. We compared the flammability of plant species at the leaf‐level (most commonly used in flammability studies) and shoot‐level (which retains aspects of plant architecture). Furthermore, we examined relationships between leaf functional traits and flammability to identify key leaf traits determining shoot‐level flammability. We collated and analysed existing leaf‐ and shoot‐level flammability data from 43 common indigenous perennial New Zealand plant species, along with existing data on leaf morphological and chemical traits. Shoot‐level flammability was decoupled from leaf‐level flammability. Moreover, leaf‐level rankings of flammability were not correlated with rankings of flammability of plants derived from expert opinion based on field observations, while shoot‐level rankings had a significant positive relationship. Shoot‐level flammability was positively correlated with leaf dry matter content (LDMC), phenolics and lignin, and negatively correlated with leaf thickness. Synthesis. Our study suggests that shoot‐level measurements of flammability are a useful and easily replicable way of characterizing the flammability of plants, particularly canopy flammability. With many parts of the world becoming more fire‐prone, due to anthropogenic activities, such as land‐use change and global warming, this finding will help forest and fire managers to make informed decisions about fuel management, and improve modelling of fire‐vegetation‐climate feedbacks under global climate change. Additionally, we identified some key, widely measured leaf traits, such as leaf dry matter content (LDMC), that may be useful surrogates for plant flammability in global dynamic vegetation models.

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Deadwood is a large global carbon store with its store size partially determined by biotic decay. Microbial wood decay rates are known to respond to changing temperature and precipitation. Termites are also important decomposers in the tropics but are less well studied. An understanding of their climate sensitivities is needed to estimate climate change effects on wood carbon pools. Using data from 133 sites spanning six continents, we found that termite wood discovery and consumption were highly sensitive to temperature (with decay increasing >6.8 times per 10°C increase in temperature)—even more so than microbes. Termite decay effects were greatest in tropical seasonal forests, tropical savannas, and subtropical deserts. With tropicalization (i.e., warming shifts to tropical climates), termite wood decay will likely increase as termites access more of Earth’s surface.

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Abstract:In the wildland-urban interface, the imperative is often to protect life and property from destructive fires, while also conserving biodiversity. One potential tool for achieving this goal is the use of green firebreaks: strips of low flammability species planted at strategic locations to help reduce fire spread by slowing or stopping the fire front, extinguishing embers or blocking radiant heat. If comprised of native species, green firebreaks also have biodiversity benefits. Green firebreaks have been recommended for use throughout the world, including the Americas, Europe, Asia, Africa and Australasia. However, despite this widespread endorsement, there has been little empirical testing of green firebreaks, particularly with field experiments. This knowledge gap needs addressing. Green firebreaks should be considered as part of the revegetation strategy following recent extensive wildfires in places such as New Zealand and Chile.Keywords: biodiversity conservation; fire ecology; green firebreaks; plant flammability; wildland-urban interface Kelly and Brotons [1] provided a timely and insightful discussion of the role of fire in biodiversity conservation, but what if the land management imperative is to inhibit fire spread?Plant species differ in their inherent flammability [2,3], and boundaries of less flammable vegetation can stop or slow down wildfire, or extinguish embers being blown ahead of a fire front [4]. Based on these principles, 'green firebreaks' are strips of low flammability species, planted at strategic locations across the landscape to reduce or slow fire spread [5], and have the potential to protect human life, property and infrastructure. If green firebreaks are comprised of native species, they can deliver biodiversity benefits such as the provision of food, habitat and dispersal opportunities for native fauna.Also known as fire greenbelts, green firewalls, green strips, and living fire breaks, green firebreaks have been recommended for use in landscapes around the world, including the United States . However, despite their extensive use, there has been little empirical testing of green firebreaks, particularly with field experiments; a knowledge gap that needs addressing. While field-based experiments should be considered the gold standard for testing the effectiveness of green firebreaks, useful insights can be gleaned using laboratory experiments, especially those that retain plant architecture by burning shoots [12,13] or whole plants [14]. Such tests could burn multiple species together to determine the relative contribution of low or high flammability species to the resultant fire [15], and hence help assess just how much biomass of low flammability plants is required to extinguish a fire that is burning a high flammability species.