Top 5 most endangered trees

Honduran Rosewood
Dalbergia stevensonii

Found in Belize, Guatemala, and Mexico, the Honduran rosewood is a beautiful and unique tree with a highly desirable purple tinted wood. Sadly it is a prime target for Illegal cross-border logging, governments are unwilling to fund or unable to control the smuggling and buyers rarely know the full story.
Peasant farmers using ‘slash-and-burn’ agriculture indirectly harm the tree by disobey rules and destroying forest habitat next to water where D.stevensoii thrives.
In 2013 protections were put in place to attempt to stop the tree’s extinction by preventing export. Anti-logging and reforestation campaigns are working tirelessly to protect the trees but growing it in a plant nursery is difficult due to insects really specific growing conditions and even the workers trying to protect this species have been killed in Guatemala.

Saint Helena Gumwood
Commidendrum robustum

Before being settled by Europeans through the east Indian company, gumwoods were once found all over Saint Helena but shortly after the trees were cut down heavily for building materials and fuel.
Gumwood timber rots quickly if exposed to the outdoors so it wasn’t used too often for building but mainly as fuel for the distillation of ‘arrack’ - a very popular alcohol. Arrack production and fires for homes ended up consuming massive quantities of wood.
The bark of the gumwood is highly palatable to sheep and almost certainly also to goats, goat extermination programs ran from the 1700’s all the way to the 1970s but the gumwoods were already all gone 1816.
The tree was thought to be extinct until it was rediscovered on a remote cliffside in 1982 but it was killed during a storm in 1986 – but then another was found. Preserving the tree is incredibly difficult because only 1 in 10,000 pollen grains will successfully fertilize a seed.
In 2010, 500 saplings were planted and are being successfully pollinated by insects but since they are all genetically similar, they are very vulnerable to disease and the species is still critically endangered.

Loulu
Pritchardia kaalae

By Raffi Kojian - http://Gardenology.org, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=12396251

loulu tree (meaning: umbrella tree) is a palm tree that grows in the west of Hawaii.
Centuries ago the early Hawaiians, cut down this tree and used the wood to make spears, ate the fruits which are similar in flavour to coconut and used the leaves were used to make fans, hats and thatching for houses.
It is a difficult species of tree to protect for conservationist as It grows slowly and only in certain locations. It can be found growing near springs, dry forests at 2,500 ft (Waianae Range).
In 1998, it was discovered that fewer than 130 remained in the wild, today, its primary threats are invasive rodents eating the seeds of the trees.

Florida Yew
Taxus floridana

Image by Richard Carter, Valdosta State University, Bugwood.org - The Bugwood Network, University of Georgia and the USDA Forest Service., CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=12349481

you can find the Florida Yew growing along the Apalachicola River in Florida.
The trees are important to humans as the bark contains the chemical ‘Paclitaxel’ a useful for combating various forms of cancer – currently sold under the brand name taxol.
The plant is critically endangered and can’t seem to regenerate itself, the remaining population is confined to a small area subject to logging and urban development along with browsing pressure from white tailed deer and beaver.
The trees have been in decline 20 years, as the number of seedlings growing is less than the number of trees being destroyed.

Three Kings kaikomako
Pennantia baylisiana

Image by Mike Dickison - Own work, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=85554699

This tree is the rarest in the world, the last remaining specimen is located on a gravelly slope on Three Kings Islands off the coast of New Zealand.
several plant species on the island were devoured by Goats until they went extinct, but the last remaining kaikomako tree survived only because it was out of reach. A recovery programme started in 2005 saw Beever and nursery manage to raise six trees that produced thousands of seeds by 2012 they had 65 trees.
The main problems is the all seedlings are derived from one tree so they lack any genetic diversity which present a very real long term threat.