Redwood (subfamily Sequoioideae) is a subfamily in the Cupressaceae family, with three genera: Sequoia, Sequoiadendron of California and Oregon and Metasequoia in China, commonly known as redwood or sequoias, massive and exceptionally tall trees.
"The combination of such a witch or wizard with a redwood wand is always intriguing, and I generally expect to hear of exciting exploits when I send this special pairing out from my workshop."
Wand-quality redwood is in short supply, yet constant demand, due to its reputation for bringing good fortune to its owner. As is usually the case with wandlore, the general populace have the truth back to front: redwood wands are not themselves lucky, but are strongly attracted to witches and wizards who already possess the admirable ability to fall on their feet, to make the right choice, to snatch advantage from catastrophe.
Behind the scenes
The fact that wand-quality Redwood is in short supply is possibly a reference to the short supply of actual Redwood (being a vulnerable species).