"The forest and vegetation are very important, the forest and the vegetation can lock in the water, when there is a flood, it can store the water, greatly reduce the impact of the flood, and when there is a drought, it can also release water to reduce the impact of drought."

"To put it simply, it's a mediator that minimizes the impact of drought and flood."

"Once the forest and vegetation are destroyed, it means that this mediation function is lost, and when there is a flood, the water is even more severe, and it is easy to burst the embankment and inundate the farmland."

"When there is a drought, it gets worse because there is no vegetation and no forests."

Liu Jin continued, talking a little messy.

However, Emperor Hongzhi and Liu Jian listened to it with relish, and seemed to think about this problem in combination with the knowledge in their minds.

"I've been to Shaanxi, and I've indeed seen the scene of heavy rain here in Shaanxi, as Gongzi said, under the heavy rain, the loess is thousands of ravines, and the soil is all washed clean."

Liu Jian is a native of Henan in the north, he has been to Shaanxi before, and he has seen it with his own eyes, so he also opened his mouth.

"The same heavy rain, in the southern region, it is difficult to cause any impact, because the southern region has many forests, vast vegetation, no matter how heavy the rain will not cause any floods, even if there is a flood, its impact can be minimized, naturally there will be no problems."

After listening to this, Liu Jin nodded, and then continued: "This north has a long history and a large population, whether it is daily life, or the construction of houses, cities, wars in all dynasties, etc., have caused great damage to forests and vegetation, of course, the biggest thing is that all dynasties have encouraged reclamation and opened mountains for fields. ”

"During the Qin and Han dynasties, the Guanzhong area was still the center, and until the Tang Dynasty, it was still the center, but now, the environment in the Guanzhong area has been completely bad, and it has gradually lost the advantage of the center."

"A big part of this is because the environment has been destroyed, and people are constantly moving south, moving to places with better environments."

Hearing this, Emperor Hongzhi thought for a while and asked, "Isn't this tree going to grow naturally, it shouldn't be cut down." ”

"How to say this problem, these 100 years of people, 10 years of trees, this tree, like people, it needs a process and time to grow."

"It may take decades, even hundreds of years for a hugging tree to grow, but it only takes half an hour to cut it down."

Liu Jin thought for a while and said, "Maybe you still can't understand, I want to think about it." ”

"Yes, let's talk about the area where the capital is located, when our dynasty was established, the mountains and forests around the capital were very lush, and there were many towering trees of all kinds.

"But since the capital was moved here, the capital has a large population, and now there are millions of people, and these millions of people, just the firewood that needs to be used every day is very huge, and it is necessary to burn mountains."

"Now, after more than 100 years, among these mountains around the capital, the tall trees have long been cut down, and the remaining small trees are also decreasing at a terrible rate, I estimate that it will not take too long, and in more than 100 years, there will be no wood to cut down around the capital."

Liu Jin thought of everything he saw when he came to the capital, the environment of this era is still very good, although the Beijing area in later generations worked hard to plant trees, engage in the three-north shelter forest and the like, but it still can't be the current environment, so take the things around the capital area as an example.

"This is indeed the case, I am in the charcoal business, and I know this very well."

When Qian Youcai, who had not spoken, heard this, he immediately spoke, and everyone also looked at it.

"I have been doing this charcoal business for more than 20 years, and this business was also taken over from my father, I remember when I was a child, when my father ran this charcoal shop, the purchase could be purchased from generation to generation near Yanjing, and all kinds of good charcoal were available."

"But when it comes to my hands, the high-quality wood in the Yanjing area has already been cut down, and now the good charcoal needs to be purchased in Shanxi, and only miscellaneous charcoal can be purchased in the Yanjing area."

"The burning of this charcoal consumes a lot of wood, but when I went to buy it, I saw that the green mountains were cut down and used to burn charcoal."

"As Liu Gongzi said, if this Yanjing area continues like this, it won't take a hundred years at all, and I estimate that in a few decades or so, all the trees in the mountains and rivers in the Yanjing area will be cut down."

Qian Youcai was a little nervous, thought about it and said.

"Is there such a thing?"

When Emperor Hongzhi, Xie Qian, Li Dongyang, Liu Jian and others heard this, they immediately frowned, they lived here every day, but they didn't notice this at all.

Originally, I didn't believe Liu Jin's words, but now that Qian Youcai came out to testify, it seems that there will be no falsehood in what he said, and he will go back and check the information again, so that people can investigate, and he will be able to know whether their words are false.

"A glimpse of the leopard in the tube, a glimpse of it, this is still the case in the Yanjing region, and the entire north has gone through a long history of development, and naturally it will not be spared."

"In addition, there are many plains in the north, which are open, and there is no forest or vegetation cover, and everything is turned into farmland, and when there is a flood, the flood is more severe, and when there is a drought, there is a vast area."

"The population in the northern region is huge, and once there is a disaster, there will be huge problems immediately, and if there is no timely disaster relief or disaster relief is not effective, people will immediately be displaced everywhere, and the sky will be full of fires."

"The southern region is much better, much better, the southern region is developed late, the damage to forest vegetation and so on is not serious, plus there are many mountains, rivers, lakes, the population is relatively smaller, the density is much smaller, and the resistance to natural disasters is stronger, even if there are any floods, droughts and the like, the impact is limited, and there are few problems since ancient times."

Liu Jin looked at the others and continued.

"In fact, in the final analysis, this is the relationship between man and nature, we take forests from nature, turn them into fields, feed more people, and nature will give all this back to us, and in the end it is we who bear all this."

After listening to Emperor Hongzhi, Liu Jian, Xie Qian, Li Dongyang and others, they were all silent, carefully thinking about what Liu Jin had just said, and what Liu Jin said today was also the first time they had heard that there was such an explanation for the rise and fall of the dynasty.