The tree on the south-eastern edge of the farm appears to have a great deal of significance. According to a few random reports, monsters live around two and a half years tops initially. However, upon "upgrading" the tree (which I shall refer to from hereonin as "The Tree") courtesy of the mysterious merchant for 2000G, monsters allegedly end up living for a whole year longer.

I've yet to confirm this myself, as my The Tree is still a little squirt. As soon as I get the opportunity, I plan on testing it. But it'll be a while.

In addition, the life peaches have apparently returned to the series according to two accounts I've read. Has anyone managed to find any strange peach-y things that appear to be somewhat peculiar?

On an unrelated note, I have to admit, there's a surprising number of people playing this import that haven't played MR before abouts the web. That's a good sign if there ever was one. More people at my other community appear to be interested in the game, too.

I've upgraded the tree once. I hope it increases the lifespan. That's a pretty cool idea.

It turns out that the The Tree doesn't require cash to upgrade. As
the years go by, it'll grow all on it's own.

My first monster, Kwagwar the Hornie, has lived far, far longer than
I expected. I got a number of retirement warnings at 2 1/2 years of
age, but my The Tree grew during this period, and my monster has
lived for a solid 3 years and 8 months, though he's in his twilight
period now. Shame he ended up with an extra year or so of old as
opposed to prime, but what can you do? At least my future
monsters will likely enjoy more fruitful primes!

Well, Kwagwar's popped it. He had a surprisingly long life of 4
years, 3 months and 2 weeks, even after being tired and stressed a
number of times.

I did a quick rest test to see how long it would live before
competing in a tourney, and it ended up dying at 4 years, 3 months
and 3 weeks. The tourney was a 6 monster round robin
competition.

Looks like tournaments appear to shave one week off lifespan.

Wow, touring abroad certainly cuts down your Internet time!

Anyway, I was raising my Mahjongkoro, which is now a geezer(s(?)), and noticed that it hit prime around the same time as my first monster, in spite of the extended lifespan. Its statgains started dropping significantly around 2 years of age. However, sometime later, my The Tree grew AGAIN. It's now very large and healthy-looking!

I'm quite certain that the first The Tree upgrade extends your monsters' lifespan, yet doesn't change the lifetime gains much, if at all. However, this second upgrade might make its prime longer. I'll find out with my next monster. Hopefully I may end up getting at least one more growth spurt out of my The Tree.

Alright, I've tested it, and not only does the second The Tree
upgrade extend the monster's prime, it also increased the drill
gains.

My Errantry maxxing Guinea-Zo, Minda (Suezo/Pixie), hit prime
about six or seven months later than both of my previous
monsters. Also, she got gains up up to 28 in individual stats at
the peak of prime during hard drills and Errantry, usually with
the monster's primary stat (Int). The highest I ever got with the
other two was 23 or 24.

It seems that in order for your The Tree to grow, you must raise
a monster 'till it nears its twilight years. While it may botch
combination efforts, you will get far better results with later
monsters after a couple of spurts. So raise a couple of sacrificial
lambs whenever you can!

May or may not be significant -
My Tree grew on my monster's 3rd birthday. It is my first monster and she has been going since the beginning of the game (no actual time spent in the freezer. Only a few pauses while I tried to generate some new monsters.)

That's about the same time my tree got its first growth spurt. It
seems pretty consistent.