Task: Question Answering
Input (English): Passage: In pre-contact times, natives traveling up Mauna Kea were probably guided more by landscape than by existing trails, as no evidence of trails has been found. It is possible that natural ridges and water sources were followed instead. Individuals likely took trips up Mauna Kea's slopes to visit family-maintained shrines near its summit, and traditions related to ascending the mountain exist to this day. However, very few natives reached the summit, because of the strict kapu placed on it.In the early 19th century, the earliest notable recorded ascents of Mauna Kea included the following:
On August 26, 1823, Joseph F. Goodrich, an American missionary, made the first recorded ascent in a single day; however, a small arrangement of stones he observed suggested he was not the first human on the summit. He recorded four ecosystems as he travelled from base to summit, and also visited Lake Waiau.
On June 17, 1825, an expedition from HMS Blonde, led by botanist James Macrae, reached the summit of Mauna Kea. Macrae was the first person to record the Mauna Kea silversword (Argyroxiphium sandwicense), saying: "The last mile was destitute of vegetation except one plant of the Sygenisia tribe, in growth much like a Yucca, with sharp pointed silver coloured leaves and green upright spike of three or four feet producing pendulous branches with brown flowers, truly superb, and almost worth the journey of coming here to see it on purpose."
In January 1834, David Douglas climbed the mountain and described extensively the division of plant species by altitude. On a second climb in July, he was found dead in a pit intended to catch wild cattle. Although murder was suspected, it was probably an accidental fall. The site, Ka lua kauka  19°53′17″N 155°20′17″W, is marked by the Douglas fir trees named for him.
In 1881, Queen Emma traveled to the peak to bathe in the waters of Lake Waiau during competition for the role of ruling chief of the Kingdom of Hawaii.
On August 6, 1889, E.D. Baldwin left Hilo and followed cattle trails to the summit.In the late 19th and early 20th centuries trails were formed, often by the movement of game herds, that could be traveled on horseback. However, vehicular access to the summit was practically impossible until the construction of a road in 1964, and it continues to be restricted. Today, multiple trails to the summit exist, in various states of use. 
Question: What is the full name of the full name of the person after whom the Douglas fir trees marking the site, Ka lua kauka, are named?
Output (English): David Douglas.