Tue, Oct 13, 2020 page14

• Experts seek solutions for endangered oriental white oaks 槲櫟生存危機加劇 專家團集思研究解危方法

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  Oriental white oaks, which in Taiwan are only to be found in Hsinchu County, are facing a renewed challenge to their survival on their home ground. A team led by Professor Chao Wei-chun of National Chiayi University’s Department of Forestry and Natural Resources spent two days at the Kengzihkou shooting range to do a survey about how well the local wild oriental white oaks are surviving. They found that one more tree had died since three months ago, while the trunks of several others had died, leaving only sucker shoots alive. At least one eighth of the 80 surviving oaks showed signs of wilting in their crowns. There were fewer acorns than last year, exhibiting differing levels of ripeness, which is a sign of delayed ripening. These findings give cause for concern.

  Chao’s team says that the reasons for the aforementioned conditions are not clear. Taking the wilting, for example, although they suspect that it has to do with insufficiently cold winters, relatively high temperatures and inadequate rainfall in recent years, there is no way to confirm this, so they are deliberating about how to prevent the situation from worsening.

  They have been doing surveys on the growth of oriental white oaks in their natural environment since 2013. They go into the restricted area every season to record the number of trees in the local oak population and measure their diameter at chest height. They also collect acorns and give them to Liao Yue-ken, a professor in the department who then uses the acorns to raise seedlings, which he gives to Hsinchu County Government for restorative planting outside the restricted area. This year they have added the further task of assessing the oaks’ state of health.

  

  A researcher inspects oriental white oak acorns at the Kengzihkou shooting range in Hsinchu County at the beginning of this month.一名研究員本月初在新竹縣坑子口靶場撿查槲櫟上的橡實。

  Photo courtesy of Chao Wei-chun照片：趙偉村提供

  Unfortunately, they say, while they recorded 81 wild oaks in their June survey, now they have to change that number to only 80 trees left, several of whose trunks have died, leaving only the suckers still alive.

  This was the first time that they found signs of delayed acorn ripening. They observed greater differences in the number and ripeness of acorns, not only within the same area, but even on the same tree.

  They saw plump, ripe acorns growing on some of the oaks, but there were also some tiny acorns that had only just formed and had not yet reached the ripening stage. There was also one tree in the same area that was only 20cm tall, yet had produced big, plump acorns. This discovery overturned their previous understanding that oriental white oaks have to be over 50cm tall before they can flower and bear fruit.

  

  Researchers from National Chiayi University’s Department of Forestry and Natural Resources inspect oriental white oaks at the Kengzihkou shooting range in Hsinchu County’s Sinfeng Township at the start of this month. 嘉義大學森林暨自然資源學系研究員本月初在新竹縣新豐鄉坑子口靶場撿查槲櫟。

  Photo courtesy of Chao Wei-chun照片：趙偉村提供

  Despite this, the overall acorn yield this year is lower than in previous years. In the past they could collect more than 1,000 viable acorns in two working days, but they only collected 500 to 600 in two days this time.

  (Translated by Julian Clegg, Taipei Times)

  全國在新竹縣僅見的槲櫟再傳其原生地的生存考驗加劇！國立嘉義大學森林暨自然資源學系教授趙偉村團隊日前連兩日進入坑子口靶場進行野生槲櫟的生存狀況調查，發現三個月來再有一株死亡，另有多株主幹也已死去只剩萌蘗。存活的八十棵中，有至少八分之一的樹冠層有萎枯現象，整體橡實量較往年少且成熟度差異大，顯示有成熟期延後的跡象，讓人憂心。

  趙偉村團隊表示，前述狀況的發生原因不明。以枯萎狀況為例，他們雖懷疑跟近年冬天不夠冷、氣溫偏高、雨水不足有關，但因無從驗證，如何防阻惡化？他們也在努力思考。

  他們從二○一三年開始執行原生地槲櫟的生長狀況調查工作，每季進入管制區掌握族群數量、胸高直徑、採集橡實，轉交該系教授廖宇賡接力用橡實育苗，再交給新竹縣政府執行管制區外的復育，今年再新增評估它們的健康狀況。

  但他們在日前的調查中，除了遺憾六月份還有八十一棵野生槲櫟的調查記錄，今天就要改寫為只剩八十棵，其中還包含了多棵主幹已經死亡只剩萌蘗的。

  另，這次也首度發現野生槲櫟的果實成熟期有延長現象，因為不僅同區的結果率、橡實成熟度差異性都極大，就連同一植株上也有相同的現象！

  他們看到有些槲櫟上掛有長得非常飽滿、已經成熟的橡實之外，卻也有剛冒出頭、處於未熟果階段的小橡實。同區還有一株僅二十公分高而已的植株，卻結出了大又飽滿的橡實，顛覆了他們認為槲櫟要有五十公分高以上才有開花結果能力的認知！

  但是整體而言今年的結果率比往年要少，以前兩個工作天就能採回破千顆可用於育苗的橡實，但這次兩天下來才採到約五、六百顆。

  （自由時報）
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