Growing up in southern indiana sinkholes are a danger we are surrounded by. There are at least 15 open sinkholes and at least that many depressions caused by collapsing under ground caverns within 5 miles of my parents house. I have 3 within a stone's throw of my property line. Ive heard stories of people in my area dumping trash and brush in sinkholes for decades and never filling them. One guy even pushed a couple old school buses in one and said they disappeared.
Id say in the case of the video, once the ground under the trees opened up the weight of the trees, the root ball and the massive amount of water and mud rushing in buried the trees under ground. Sinkholes can be funny, not haha but more strange I guess. You may think its filled in a stable then itll open up again or worse open up in another location close by.
When my brother and I were kids we played in the woods at my parents house. There is a huge bowl depression in the woods, its almost perfectly round. We always thought it was once flat but a cavern close to the surface collapsed leaving the bowl. In the bottom there are two holes about 4 or 5 feet across and when it rains water runs down and into the holes. It doesnt matter how long or how hard it rains, the bowl never fills, the rain water just disappears. Less than 100 yards away on the neighbors property there are two more of these large depressions. The one on my dads property is at least 200 yards across and the neighbors' are comparable in size. I was down in the depression a couple months ago on my atv after a big rainstorm scouting some downed trees for my father in law to cut for firewood and the holes were wide open. I could see at least 10 feet straight down into the bigger one til it took a turn out of sight. About 3 months before that they appeared to be mostly closed off.
You literally cant drive 1 mile in my area without seeing a sinkhole or one of these huge depressions. My high school was built over 6 of them and we all heard stories of a CAT dozer that became stuff so bad in a hole that it was abandoned and the school was built over it. Dont know how much truth there is to that tho.
We also have 3 big cave systems under the area. Marengo caves in Marengo Indiana has tours. So does Squire Boone caves which is less than 2 miles from my house.
A new tour just opened in Corydon, opened to the public in May. The cave they tour is part of the Binkley cave system and its one of the largest in the state of Indiana at nearly 35 miles of underground passages. The sinkholes at my dad's house are part of this system. The new tour is called Indiana Caverns and even includes an underground boat ride.
Heres a link to the site: http://indianacaverns.com/m/
I havent gone on the tour yet but plan to.