California has lost half its big trees since the 1930s, according to a study to be published Tuesday and climate change seems to be a major factor（因素）.
The number of trees larger than two feet across has declined by 50 percent on more than 46, 000 square miles of California forests, the new study finds. No area was spared or unaffected, from the foggy northern coast to the Sierra Nevada Mountains to the San Gabriels above Los Angeles. In the Sierra high country, the number of big trees has fallen by more than 55 percent; in parts of southern California the decline was nearly 75 percent.
Many factors contributed to the decline, said Patrick Mclntyre, an ecologist who was the lead author of the study. Woodcutters targeted big trees. Housing development pushed into the woods. Aggressive wildfire control has left California forests crowded with small trees that compete with big trees for resources（资源）.
But in comparing a study of California forests done in the 1920s and 1930s with another one between 2001 and 2010, Mclntyre and his colleagues documented a widespread death of big trees that was evident even in wildlands protected from woodcutting or development.
The loss of big trees was greatest in areas where trees had suffered the greatest water shortage. The researchers figured out water stress with a computer model that calculated how much water trees were getting in comparison with how much they needed, taking into account such things as rainfall, air temperature, dampness of soil, and the timing of snowmelt（融雪）.
Since the 1930s, Mclntyre said, the biggest factors driving up water stress in the state have been rising temperatures, which cause trees to lose more water to the air, and earlier snowmelt, which reduces the water supply available to trees during the dry season.
There are lots of ways to raise awareness for a cause. Usually, the 1 the idea is, the more it gets noticed. And that's precisely why one 2 Frenchman has caught our attention.
Baptiste Dubanchet is biking across Europe, surviving 3 on discarded（丢弃）food. The three-month, 1 900-mile journey from Paris to Warsaw is Dubanchet's 4 of raising awareness of food waste in Europe and throughout the world.
As you can 5 , the trip is no piece of cake. While restaurants 6 tons of food each year, much of it remains inaccessible because of 7 garbage containers, health regulations, or business policies. Only about one in ten places 8 him food that would otherwise be discarded.
For legal 9 , most restaurants have a policy against 10 food waste. "Some people have even 11 their jobs by giving me food," Dubanchet said.
What's 12 interesting is the attitude various cities have toward Dubanchet's cause. Berlin has been the 13 while the most difficult was the Czech town of Pilsen. There, he had to 14 at some 50 different stores or restaurants before finding food. The 15 is all the more serious when you consider the 16 exercise required to bike from France to Poland.
"I have to get food 17 because after all the biking I am tired and I need the 18 ,"
Dubanchet explained. "Is my 19 full or empty? That is the most important thing, not what I am eating."
He aims to 20 his journey by mid-July. With any luck, he'll turn a few more heads in the process.
Parents everywhere praise their kids. Jenn Berman, author of The A to Z Guide to Raising Happy and Confident Kids, says, "We've gone to the opposite extreme of a few decades ago when parents tended to be more strict." By giving kids a lot of praise, parents think they're building their children's confidence, when, in fact, it may be just the opposite. Too much praise can backfire and, when given in a way that's insincere, make kids afraid to try new things or take a risk for fear of not being able to stay on top where their parents' praise has put them.
Still, don't go too far in the other direction. Not giving enough praise can be just as damaging gas giving too much. Kids will feel like they're not good enough or that you don't care and, as a result, may see no point in trying hard for their accomplishments.
So what is the right amount of praise? Experts say that the quality of praise is more important than the quantity. If praise is sincere and focused on the effort not the outcome, you can give it as often as your child does something that deserves a verbal reward." We should especially recognize our children's efforts to push themselves and work hard to achieve a goal, "says Donahue, author of Parenting Without Fear: Letting Go of Worry and Focusing on What Really Matters." One thing to remember is that it's the process not the end product that matters."
Your son may not be the best basketball player on his team. But if he's out there every day and playing hard, you should praise his effort regardless of whether his team wins or loses. Praising the effort and not the outcome can also mean recognizing your child when she has worked hard to clean the yard, cook dinner, or finish a book report. But whatever it is, praise should be given on a case-by-case basis and be proportionate(相称的)to the amount of effort your child has put into it.