Stories: Revenge of The Dynamite Tree

If you're a mother and you can't drive, how are you going to send your kids to school many kilometers away? Some mothers choose to hire a driver, while others take a boat or an aeroplane. This mother that you're about to meet, straps her kids onto high explosives and rockets them to destination. She is known by many names, such as the sandbox tree, the monkey-no-climb tree, or more accurately, the dynamite tree. In fact, her Latin name Hura crepitans literally translates as the cracking (sound of explosion) tree. 

Hura crepitans (Euphorbiaceae).

 

Inspired by the dynamite tree's mind blowing strategy, I was determined to collect as many seedpods as possible for experimentation. Despite being native to the Amazon rainforest, Hura crepitans is widely cultivated in parks and gardens of Malaysia as an ornamental shade tree. Finding a tree isn't hard, but getting to its explosive seedpods can be tricky. That's how my dear aunt learnt it the hard way, and this is her remarkable story with the dynamite tree. 

 

Hura crepitans, seedpod.

Just so you know, my aunt is an avid gardener who fancies all sorts of exotic ornamental plants. She was on a mission to collect me the infamous seedpods of Hura crepitans. In fact, she got herself a secret weapon, which was an umbrella! Not to shield herself from kaboom, but to hook the dangling Hura seedpods that were few meters tall, taller than an average adult. We have a huge row of dynamite trees right in front of the Penang Botanic Gardens, so target was within reach. Unfazed by unpredictably loud boom, coupled with her sharp eyes and secret weapon, the bomb was quickly rendered on the ground. A piece of cake, but fate has other plans. As my aunt squatted down to collect her prize, the dynamite seedpods decided that it's time to explode. Boom! (actually it sounds like a crack) and so it went, bits and pieces  were scattered here and there. The seedpod was gone, now what?  Frustrated, my poor aunt stood up and instinctively leaned her hand onto the dynamite tree's trunk... Oh my gawd, Ooouchhhhh !!!  

 

Dynamite tree trunk. Note the sharp woody thorns.

What a bummer! I suppose we will forever remember that a dynamite tree is also called monkey-no-climb for good reasons. We might need extra thick gloves instead of an umbrella next time. No more next time for my aunt unfortunately, she's had enough HaHaHa. But don't worry, I've collected more dynamite pods myself following this enlightening experience. Join me to thank my aunt again for her sacrifice and don't lean on any Malaysian street trees without careful inspection of its trunk. 

 

Hura crepitans, flower.

The dynamite tree's seedpod had been extensively studied by science. It can explode with such a violence, the seeds are propelled at a speed of about 200 kilometers per hour! This seed dispersion strategy is called explosive dehiscence, and it's a trait that is common to many plants of the Euphorbiaceae family. What makes the dynamite tree remarkable is that its seeds are large, and they are shaped like discs to reduce air resistance and facilitate propulsion through the upper canopy. The dynamite seedpod contains fibers that gradually build up elastic strength when they dry. Up to a point, the outer casing weakens, and the ultra-tense fibers relax, causing an explosion. In some studies, Hura seedpods can dry as much as 65% of its original weight before exploding. That's important for a tree that's living in the Amazon rainforest because it will want to spread its seeds far and wide at all costs. As with all Euphorbiaceae plants, Hura crepitans is also poisonous, potent enough to be used as an arrow poison capable of killing the anaconda snake (according to local sources). It contains highly irritating daphnane and phorbol esters, which we will encounter my [Science] articles. All in all, the dynamite tree is a remarkable species with explosive seedpod, poisonous sap, and nasty tree trunk. What better stories to tell than poison and explosion?