If you like to take a walk in the woods in the United States or you prefer to decorate a tree at Christmas, you should know that climate change is making both of those activities a lot more ___________.

Looking at two ___________ and economically important species - the Douglas fir and the Ponderosa pine -scientists found that fires and drought _____________ by climate change make new growth difficult, especially in low-elevation forests, according to a study published Monday in the Proceedings of the National Academy of Sciences.

Some forests in four regions in California, Colorado, the Northern Rockies and the southwestern part of the United States have crossed ''a(n) ___________ climate tipping(转折)point for post-fire tree generation, '' the study says.

Climate conditions over the past 20 years have _____________ changes that would have taken decades or even centuries to ___________ across broad regions of the country. This is leading to the sudden _____________ of trees and making these lands increasingly unsuitable for tree regeneration.

''Climate changes is _____________ our forests now, not just in some distant future. Maybe in areas where there are really _____________ seed sources, there could be some trees, but it is becoming really hard to get these trees back due to climate change, '' said study co-author Kim Davis.

The problem probably won't get any better, as climate change is making intense wildfires much more ______________. Western foresters say there used to be a fire season. But devastating and ____________ fires have become a reality all year long. In 2018, fire cost California more than $9.05 billion, according to the USA insurance commissioner, the deadliest and most destructive wildfires season in the ________________ history.

A higher number of fires and low seed availability means a high probability that these trees in these regions won't come back, Davis said. This study ______________ on the driest and hottest areas of the Western forests, but researchers will next try to focus on how much will be impacted.

____________, there are some things people can do to ease some of this problem. Forest management plans that reduce high-severity burns can help. Increasingly, forest managers are considering allowing some fires to burn under more moderate conditions, Davis said, Forest ______________can also replant trees after fire, at least in the areas where climate conditions will allow.

Where's winter? A number of countries just witnessed their warmest January ever recorded.

It's not just you — January was ________ than usual for many parts of the world.The global temperature last month was warmer than every previous January on record, just ________ out the previous record from January 2016, the Copernicus Climate Change Service reported.And in Europe, it was the warmest January ever recorded at 0.2ºC warmer than the previous record in 2007, the European Union's system for ________ the Earth said.

The rise is even more ________ through the lens of history —   ________ to the average January temperature in the pre-industrial years before the 20th century, it was about 1.4 degrees Celsius (2.7 degrees Fahrenheit) warmer.

Last month, temperatures in Europe were warmer than the 1981-2010 January average, especially over parts of northern Europe, the report said. Some areas were more than 6°C above the average, ________ overall, it was 3.1°C warmer than the average January in that time period.It also brought the warmest January day ever recorded in Norway, which saw the second warmest January overall since 1900.And in Central and southern Finland, it was its warmest January recorded since 1961.The heat wave ________ to several parts of Russia, too.Temperatures from east of Greenland to the northwest of Svalbard were warmer, and had below-average sea-ice cover.

________, last year was 0.59°C warmer than the 1981-2010 average. That's the second warmest year on record. The warmest 12-month period remains October 2015 to September 2016, where it was 0.66°C ________ 1981-2010. Those averages are pushing global temperatures ________ to red lines set by both climate scientists and world leaders. Scientists have ________ that global temperatures should be kept well below 2 degrees Celsius (3.6 degrees Fahrenheit) of ________. The international community, as outlined through the Paris Climate Agreement, stated that participating countries would ________ to keep global warming limited to 1.5 degrees Celsius.

But ________ with a rise since pre-industrial temperatures, last month's average is between 1.2 and 1.4 deg C of warming —   putting it near the Paris Climate Agreement's ________.

Recently, a small group of bird-watchers spent three weeks around Mount Vernon. They were busy _______ wild birds on Mount Vernon’s wetlands, south of Washington, D.C. They began in the middle of December and _______ until the beginning of January.

The bird-watchers were among 70,000 volunteers who collected _______ for the National Audubon Society. Its first “Christmas Bird Count” took place 115 years ago in 1900 _______ a man named Frank Chapman suggested a new Christmas _______ that people count birds _______ shooting them around the holiday.

Harry Glasgow _______ the Christmas Bird Count 10 years ago. This year, he was one of the volunteer bird-watchers at Mount Vernon. “I think it’s great _______ of a lot of talent around the nation to keep track of birds. Birds are one of the _______ signs of the health of the ecology.”

Last year, the bird count ________ over 66 million birds of 2,403 different species. Over half the birds in North America — 314 out of 588 species — are seriously ________ by climate change. The impacts cut across all birds, all sizes, all kinds, and all places.

Information from the bird counts has shown that birds are ________ farther north during the winter months because of ________ weather. Bird-watcher Jaime Reidy has noted the difference close to Washington, in the state of Virginia. “You get to see them at ________ times of the year, a little earlier, ________ a little later.”

Gary Langham says other conditions are affecting bird ________. “You can imagine the number of the birds that live along the beach or along the rocky shoreline as sea level is ________ because of global warming around the world.”

David Yarnold says, “Christmas Bird Count data are becoming important not only in ________ current climate change, but in judging the future ________ of climate change on North American bird populations. If we know what to expect, we can start taking ________ now to do something about it.”