在2020年在美國加州紅杉州立公園，因『天然因素-閃電』所發生的森林大火中，有部分的紅杉(Sequoia sempervirens) 是倖存下來的，相當令人驚訝。2023年學者在Nature Plants期刊中發表的『Old reserves and ancient buds fuel regrowth of coast redwood after catastrophic fire』文章指出幾項原因，我們整理如下：
火災後的樹木生存
在2020年的大火中，這次大火影響到樹木的樹冠，導致紅杉針葉被燒毀，但有一部分的紅杉是倖存下來的。
大多數樹木的根、樹幹及樹冠都被燒毀，因此也造成樹木的光合作用能力受損。
樹木的能量儲存
研究發現，即使紅杉的針葉被燒毀，倖存者仍然能夠利用過去長期儲存的碳來恢復生長。
燒毀的樹木透過根部、樹幹和樹枝重新發芽而恢復生長，學者認為這是樹木得到碳儲存的營養支持。
這些能量儲存，是來自幾十年前植物經由光合作用製成的糖，儲存在樹體之中，可以重新讓樹木生長
從古老的碳提供能量而萌發新芽，對於具有千年壽命的生物體來說，能夠在罕見但災難性事件中生存的特徵可能代表著樹體中存在著重要的能量庫。 樹木受到干擾後，可以利用數十年前的光合作用產物，讓樹木可以重新活化。
能量儲備的利用
燒焦的樹木會利用儲存在樹皮下的碳，讓樹木重新萌芽。
這個發現挑戰了先前對樹木生長的理解，也顯示樹木有能力應對氣候變遷引發的災難性火災。
研究人員使用放射性碳定年方法，評估燒焦後，讓樹木生長碳儲存的年代。
研究結果顯示這些紅杉植物體內的碳儲存是可以追溯到數十年前，甚至是一個世紀前。
樹木的長壽和新生
由於紅杉具的壽命可長達2000多年，這次發現從古老的樹體中提供的碳，在這次火災後已經有部分的芽萌發出來，而讓這些芽萌發出來的營養物質，可以追溯到 1000 年前，研究人員認為這可能是有記錄以來最古老的。
對於具有千年壽命的生物體來說，能夠在這次的森林大火的事件中重獲新生，顯示出植物體過去儲存的碳是可能是重要的能量庫。
未來挑戰
雖然樹木已經長出新的芽，但科學家認為因為樹冠葉片的損傷，要恢復到原始在光合作用所能儲存的能量，仍然是比較困難的，因此對於其生長能力仍舊感到擔憂。
同時，未來對於可能發生的第二次森林火災，樹木是否能夠再次利用儲存的能量，尚不清楚。
這項研究也顯示出紅杉具有令人驚奇的適應能力，能夠在極端條件下生存並重新生長。
In 2020, a devastating wildfire swept through California's Sequoia National Park, leaving an indelible impact on the iconic coast redwood trees (Sequoia sempervirens). Despite the destructive forces of nature, a notable number of redwood trees displayed remarkable resilience and managed to survive. The insights gleaned from a study published in the 2023 issue of Nature Plants, titled "Old Reserves and Ancient Buds Fuel Regrowth of Coast Redwood after Catastrophic Fire," shed light on the key factors contributing to the trees' ability to endure and recover.
Survival of Trees After the Fire
The 2020 wildfire significantly affected the tree canopy, resulting in the destruction of redwood needles. However, a subset of redwood trees demonstrated their ability to withstand the wildfire's impact, highlighting their capacity to endure adverse conditions.
Most trees experienced damage to their roots, trunks, and canopies, compromising their photosynthetic capacity.
Utilization of Tree Energy Reserves
The study revealed that surviving trees could tap into long-term energy reserves, even after the destruction of their needles. Burnt trees initiated regrowth through sprouting from roots, trunks, and branches, utilizing stored carbon nutrients to support their recovery.
These energy reserves, accumulated over decades through photosynthesis, were stored in the buds of the trees, enabling them to resume growth.
Sprouting from Ancient Buds
New growth emerged from buds that had been dormant for centuries beneath the bark. For organisms with a lifespan of over a millennium, the ability to survive rare but catastrophic events represents a crucial energy reservoir. The reactivation of photosynthetic products dating back several decades suggests the presence of significant carbon in the ancient tree cycle.
Utilization of Energy Reserves
Charred trees utilized the stored energy reserves beneath the bark, injecting it into the desiccated buds. This finding challenges previous understandings of tree growth, demonstrating their capacity to adapt to catastrophes triggered by climate change-induced wildfires.
Research Methodology
Radiocarbon dating techniques were employed to assess the age of the energy reserves supporting the growth of new plants in burnt redwood trees.
Results indicated that the energy reserves within these redwood plants could be traced back several decades, if not a century.
Longevity and New Growth of Trees
Given the potential lifespan of over 2000 years for coast redwoods, the discovery of sprouts emerging from ancient buds dormant for centuries beneath the bark suggests a remarkable adaptation to survive and regenerate after the recent forest fire. Some of these sprouts can be traced back to a thousand years, possibly making them the oldest recorded buds.
Future Challenges
While new buds have emerged, scientists express concerns about the difficulty of restoring the original photosynthetic energy storage due to damage to the tree canopy. Additionally, uncertainties persist regarding the trees' ability to tap into energy reserves in the event of a second forest fire. This study underscores the astonishing adaptability of coast redwood trees, showcasing their ability to survive and regenerate under extreme conditions.
參考文獻：Peltier D.M.P., CarboneM.S., Melissa Enright M., Marshall M.C.,Trowbridge A. M., LeMoine J., Koch G. & A. D. Richardson (2023) Old reserves and ancient buds fuel regrowth of coast redwood after catastrophic fire. Nature Plants. DOI: 10.1038/s41477-023-01581-z.