So did you bring home a Norway spruce or a Douglas fir? Or is it a grand fir or a Fraser fir? I’ll bet the guy at Home Depot didn’t have a clue.

The Brooklyn Botanic Garden has a great click-through tool on its Web site that guides you to a proper identification based on what the needles, buds and twigs look like. Here’s a link.

The site also has a good description of all 15 commercially grown varieties of holiday trees, including advantages and disadvantages as indoor Christmas trees.

My favorite for the last few years has been the Canaan fir, but it’s hard to find. It’s got a nice full look, but still has lots of room between branches for ornaments. Gentle on the hands, too. Any other favorites out there?

Here’s some more info on Christmas trees from the Brooklyn Botanic Garden, including how-to-shop-green info, pesticide concerns and potted live trees that can then go outside:

“Whether assessing one’s carbon footprint, or looking at the footprints in the snow on the way to the tree farm, there is no doubt that this year there is a “greenâ€? consciousness growing among holiday revelers. Many are searching for answers on ways to reduce the environmental impact of some traditional holiday activities—including the purchase of a seasonal tree.

“Each year, Americans purchase more than 30 million fresh-cut holiday trees. But now, with a “greenâ€? awareness growing among holiday revelers, traditionalists and environmentalists alike are asking, “Is it environmentally sound to decorate with a cut tree, or should we find an alternative?â€? Following are some considerations the experts at BBG offer to help eco-conscious buyers make the “greenestâ€? choice possible:

“Most fresh-cut holiday trees are grown on dedicated tree farms in the U.S. and Canada. This is a positive: natural or virgin forests are not harvested (but to be sure, ask the tree seller where his product comes from). Tree farms are generally beneficial to the environment because, while growing, the trees help absorb carbon dioxide.

“However, there can be some negatives with farmed trees: If the growers use pesticides, residue can remain present on the tree leaves and bark after cutting. And trucking trees long distances to bring them to the tree lot near you increases the carbon footprint of the trees significantly. If these matters concern you, try to find a local tree farm that grows its plants organically.

“Most artificial trees are made overseas from PVC and other harmful products. Reusable plastic trees help you avoid chopping down a tree each year, but most artificial trees are made from polyvinyl chloride (PVC) and other products that are harmful to one’s health. The carbon-load of artificial trees is also quite high: most of the trees are made from petroleum-based ingredients, and 85 percent of them are made in China, requiring significant burning of fuels for shipping to the U.S.

“However, artificial trees are not all bad: Some come pre-strung with LED lights, which are 90 percent more energy efficient than incandescent lights. LED lights also do not heat up and therefore do not pose the same fire risk as conventional bulbs.

“Many tree species are available live in pots, and can be planted outdoors after the holidays. Perhaps it’s time to start a new family tradition: a potted fig or pear tree next to the fireplace. Many conifers are also available in pots at nurseries. Be sure to buy a tree that is appropriate to the USDA climate zone where you live, and plant the tree out within a reasonable amount of time after the holidays so that it does not die.

“Many cities and towns now offer holiday tree recycling and mulching programs. If you choose to buy a fresh-cut tree, check with your local government’s sanitation and parks departments to find out if they have tree recycling programs. Some cities do special trash pickups for holiday trees to divert them from landfills. And some local organizations arrange holiday tree mulching programs.

“If you decorate trees in your yard with lights, remove the lights once the holidays are over. Light strands wrapped around tree limbs can strangle—and even kill—a tree as it grows.

“All information can be found at bbg.org/holidaytrees.”