Hikers and researchers in the deep backcountry of Hawai'i often find the oddest trees in the strangest places, and wonder how they got there.

A cluster of kukui trees: Does it suggest an ancient Hawaiian settlement, since kukui was a Polynesian introduction to Hawai'i, and its oily nut was used to make candles?

A stand of Hawaiian fan palms or loulu: Have they been growing in that location since before human arrival in the Islands?

Another stand of a similar-looking tree, the introduced Chinese fan palm: It was clearly not native, so how did it end up in the deep woods?

The blue-flowered Pride of India, known in Hawaiian as 'inia, stands in gullies and dry hillsides around the state: Where did that come from?

The answer, in many cases, is that they came by air.

Territorial foresters 75 years ago were faced with vast areas in the Islands that were eroded by cattle and goat grazing, denuded by fire or overwhelmed by monocultures of the fern known as uluhe.

In one Kaua'i response in November 1929, foresters arranged for the use of a Fokker aircraft from the Army Air Corps. They loaded up for three flights over the island, with a total of 1,689 pounds of varied seed. The seeds were from 'inia, the New Zealand karaka tree, ironwood, Java plum, kukui, unspecified eucalyptus, African tulip and both the native loulu and Chinese fan palms, according to an article printed in a 1929 issue of The Garden Island newspaper.

They flew from the old Port Allen airport, up through Pu'u Ka Pele, Koke'e and Kalalau, across the Makaweli uplands to Wai'ale'ale, across the Hanalei and Wailua River valley uplands and back to Port Allen. Dumping seeds all the way.

During the same year, the aircraft were used to drop assorted seeds on the site of a major forest fire on the Big Island.

On O'ahu, the planes were used to drop pot-grown seedlings into fields of uluhe, in hopes an already-sprouted plant could get its branches above the fern cover before its growth was halted by the lack of sunlight under the fern.

In each case foresters said they experienced some success. Some of their seeds and their seedlings grew.

Then there is the perhaps apocryphal story of the koa bin, in which territorial foresters are said to have mixed koa seeds from all islands as a way to promote vigor, and spread them over the countryside — leading to the mystery, is the koa tree you see actually originally from the island you're on?

If you have a question or concern about the Hawaiian environment, drop a note to Jan TenBruggencate at P.O. Box 524, Lihu'e, HI 96766 or jant@honoluluadvertiser.com. Or call him at (808) 245-3074.