If you own a house with some trees on the property, you probably don’t think about them much unless they require maintenance—and in those moments you think of them as expenses. Sure, those trees have value due to their natural beauty and shade (or possibly the fruit they grow), but few people think about the trees in their yards in terms of having a monetary value.

But you should, because trees on your property actually do have value—and that value is often substantial. First of all, maintained trees in good condition add property value in general—as much as 15%. But some species of tree can be worth a lot of cash if they’ve been allowed to grow to enormous proportions in your yard—a nondescript elm tree with a 20-inch trunk, for example, might be worth as much as $30,000. And some trees have been appraised for more than six figures. Some trees are so valuable poachers actually invade people’s property to steal them.

If you’re currently peering out your window at the trees in your yard and wondering if you’re sitting on some sort of woody goldmine, here’s how to find out the tree value on your property.

Online calculators

The simplest way to get an idea of how much your trees might be worth is to use an online calculator like this one, which uses the USDA Forest Service’s i-Tree software, or the slightly simpler ones here. These calculators rely on you to input accurate information, so you might need to sleuth out the species of your tree and do some measurements and observations in order to get a truly accurate valuation.

It’s important to note that these tools offer a sense of the value your trees are adding to your property—by providing shade, cleaning the air, removing carbon, and cooling your home. If the calculator says your tree is worth $15,000, you probably can’t just sell it for $15,000, or add that amount to your home’s listing price when you sell your house. But these tools do offer a starting point for valuing your tree.

Tree appraisal

If you want to get a more accurate value for your tree, you’ll need to hire an arborist to conduct an appraisal, which is a real, actual thing with a lot of science behind it. You can find a consulting arborist at the American Society of Consulting Arborists (ASCA) website.

Tree appraisals are mostly used to determine insurance values in case your trees are damaged, destroyed, or improperly removed from your property and you need to make a claim. But you can sell a tree from your yard if the tree is valuable enough, and if you can find a nursery or other entity interested in buying it. And if you have a lot of hardwood trees on your property, you can find companies like Sell Your Trees that will pay you for them, then come and remove them at their own expense (making an appraisal even more important so you know you’re getting fair value for your trees). If your trees are valuable and mature (meaning they’re fully grown and not a sapling, like the trees you buy at a nursery), you can also sell them on an online marketplace like Re-Tree, which can also give you an idea of how much that specific tree is worth.

The most valuable and easiest to sell trees (based on Re-Tree’s catalog) include:

Japanese Maple. These majestic and colorful trees can sell for $400 to more than $8,000 depending on health, maturity, and specific type.

Flowering dogwood. Whether pink or white, these beautiful trees can be worth as much as $4,500.

Tricolor beech. This ornamental tree changes colors with the seasons, making it a beautiful addition to any landscaping project, and can sell for as much as $8,000.

Gingko. These slow-growing trees are terrific shade trees, and can sell for $5,000 to $6,000 each.

Black Walnut. The wood of the Black Walnut is valuable for furniture makers, and can sell for as much as $2,500.

Even if the trees in your yard aren’t super unique and rare, you can still often sell them for a few hundred bucks if they’re healthy and mature. If you’re looking to monetize your trees, it’s worth having them appraised and seeing what the market will bear.