博彩平台推荐的科学家进行了40年的人口普查研究，发现气候变化使树木死亡率增加了两倍，并阻止了树木的再生

Criticizing the Biden administration’s $3.5 trillion Inflation Reduction Act, a U.S. Senate candidate in Georgia singled out funding to plant and protect trees.

“They continue to try to fool you that they are helping you out. But they’re not. Because a lot of money, it’s going to trees,” GOP candidate Herschel Walker said while stumping at a fundraiser. “We got enough trees—don’t we have enough trees around here?”

A 2015 study in Nature estimated there are 3 trillion trees on the planet. Whether or not that’s “enough,调查还发现，“自人类文明开始以来，全球树木数量减少了约46%。.”

博彩平台推荐的一位科学家在40多年的时间里一直在监测科罗拉多高原地区的树木健康和数量, 在过去的二十年里，气候驱动的温度变化和干旱不仅使树木死亡率增加了两倍, but also significantly undermined tree regeneration rates. 

And that matters.

“If we are losing forest cover, we are going to lose a variety of ecosystem services,” says Tom Veblen, Distinguished Professor emeritus of geography, 他从1982年就开始追踪博尔德以西尼沃特岭数千棵树的变化. 

随着泥石流和洪水的增加，树木覆盖面积的减少会对流域造成破坏, and in the loss of habitat for certain species. Perhaps most destructive, the loss of “above-ground biomass” removes a vital source of carbon storage, which further fuels climate change. 

“In most simulation models of ecosystem impacts of climate change . . . the trees grow back after fire. 但博彩平台推荐在科罗拉多州的山地森林中没有看到这样的记录，”凡勃伦说. That results in “one of those nasty, 有些意想不到的正反馈循环加速了气候变化，因为大气中有更多的二氧化碳. Even a politician in Georgia will potentially be affected by that.”

1981年，凡勃伦在智利和新西兰进行了六年的研究后来到博彩平台推荐, 这让他明白了建立可以长期观察树木的地块的价值. 

“根据我在南半球的研究经验，我知道我想要建立永久性的森林地块, which are essential for understanding long-term changes in tree populations,” he says. “There is no substitute for that.”

With money from a short-lived program funded by the state of Colorado, he and his students established 40 “long-term monitoring plots,” marked 8,000 trees on Niwot Ridge and have been monitoring them ever since. 

“The proposal . . . 是评估气候变率对树木数量和种群变化的影响吗, mortality, and the establishment of new seedling recruitment (new trees),” Veblen says. 第二个目标是研究19世纪大火对低海拔黄松和花旗松森林的影响.

Veblen研究的一个重要发现是:直到1994年，树木的死亡率一直很低且稳定, they have tripled since then, even in higher elevation Englemann spruce and lodgepole pine forests. 

“That’s not at all surprising . . . given increasing temperatures and increasing drought,” Veblen says, 他指出，研究人员在美国西部各地都得出了同样的结论.

Meanwhile, new trees are not filling in the gaps.

Former CU Boulder graduate student Robert Andrus, now a postdoctoral researcher at Washington State University, harvested about 1,用1000棵幼树来确定它们的生长日期，并发现新树在“单一年的脉冲”中生长, cooler, moister years, based on late spring and summer weather conditions,” Veblen says. 

但在安德鲁斯研究的70年记录的后半段，这种年份的出现率下降了三分之二. 

“Without cool, moist years, we’re not getting establishment” of new seedlings, including after fires, Veblen says. “That’s an indicator of what is likely to continue with warming temperatures.”

Even lodgepole pines, 在一些地方，以殖民烧伤地区而闻名的树木的球果在暴露于火后会打开，但却无法再生. 在2002年被严重火灾烧毁的路特和白河国家森林中，在15年的时间里反复采样, there are only sparse and patchy seedlings of this fire-adapted species, which usually take root within a year or two. 

这些趋势使凡勃伦和其他研究人员以及森林管理者相信，西方森林需要人类的帮助, particularly after destructive wildfires. 

“如果博彩平台推荐想在火灾后拥有森林，博彩平台推荐就不需要依赖自然再生. We need to invest heavily in artificial regeneration,” the cultivation and planting of seedlings in strategic areas, Veblen says.

Andrus agrees. “博彩平台推荐有树皮甲虫爆发和野火，导致科罗拉多州树木明显死亡. 但博彩平台推荐的研究表明，即使是在人们徒步旅行的地方，在森林看起来很健康的地方, mortality is increasing due to heat and dry conditions alone,” adding:

“It’s an early warning sign of climate change.”

Veblen和消防管理界普遍认为，“与火共存”越来越具有挑战性, as shown by modeling projections that say, “Exceptional fire seasons like 2020 will become more likely, 据预测，未来极端天气下的野火活动将超过以往任何时候.”  

In Wildland Urban Interface areas, so-called “red zones” that are abundant throughout the West, 凡勃伦提出了建议:业主仍然必须建立“可防御的空间”.” Building codes should be used to require less-flammable building materials. 通过砍伐树木和规定的火灾相结合的“减少燃料”应该优先考虑在定居地区附近，给消防员一个立足点. 

However, Veblen says, in more remote areas, mechanical thinning alone is not effective and not practical. Instead, he says, 管理人员越来越强调让野火减少燃料和缓冲未来火灾可能性的价值.  

“各机构以前倾向于强调机械减薄以减少燃料, 而是在助长2020年东部麻烦火灾的极端天气条件下发生的, 任何实际数量的燃料管理都不能完全保护家庭和社区,” he says.

Instead, 他希望看到目前用于偏远地区减少燃料的资源被重新定向到苗木培育和种植中, suitable areas.

“We are not going to be able to prevent large, severe fires, 因此，博彩平台推荐需要更有战略地投资博彩平台推荐的资源，以避免或延缓气候变化的一些最坏后果,” he says.