By Katinka Ruthrof
As you may be aware, we have a seed collection program for Yalgorup National Park (Bulletin 10). We collect seed for a number of reasons, including: to conserve the genetic resource for the area, to undertake restoration trials and carry out broadscale restoration elsewhere.
Late last year we had another seed collection day (technically it’s fruit collection, rather than seed collection) and over 10 people came to help. We were walking towards our first tuart (keeping one eye out for any ticks) when we noticed a number of tuart opercula on the ground. Opercula (Latin for ‘little lid’) are caps which protect the flower during maturation.
Looking more closely into the canopy, we saw that the tree contained a large number of flower buds. Then the next, and the next… almost all of the tuart trees that we saw contained flower buds. This was exciting! These trees have been stressed since the mid 1990’s and we haven’t seen a mass flowering event in this part of the park since.
Until recently, very little was known about tuart reproduction (e.g. cycle of bud production, flowering times, number of seeds/fruit etc.). What we do know (from studies in other parks and anecdotal evidence) is that tuart has a very irregular and intermittent flowering, which leads to a variable seed production and supply (hence seed collecting is not as easy as one would think). For Yalgorup National Park, this intermittent flowering, on top of the massive decline that is occurring, has resulted in very low levels of fruit and seed.
This has larger scale implications for areas with declining eucalypts. Without canopy stored seed, management interventions such as prescribed burns will not facilitate eucalypt seedling recruitment. Indeed, fire at this time could cause massive changes in community structure and facilitate weed invasion. But that’s another blog topic…
Where to go from here? Well, in many temperate eucalypts, flowering occurs one or more years after bud initiation, followed by one year of fruit development. So, if all goes well, the buds will develop into flowers and the flowers will be pollinated, develop into fruit and set seed. Then hopefully the fruit will survive any pre-dispersal seed predators (e.g. those with beaks). If all that falls into place, book it into your calendars everyone, next summer we will hopefully have plenty of tuart seed to collect.
Nice Tink to read about your findings. I was just wondering if the mass flowering is occurring in other woodlands as well?
Hello fellow tuart watchers
I have been closely observing Tuart trees in and around Bunbury and most of them are producing prolific amounts of flower bud. There is an amazing litter of operculums under some trees.
I was expecting a spectacular mass of flowers, much like that seen in marris, jarrahs, red flowering gums etc. However, I was quite disappointed as it seems that when the bud cap drop, a very short amount of time elapses before the cream coloured stamens are either blown away by rain, or wind or just shrivel up and disappear. Some bud caps clasp the stamens so tightly that they also pull them off.
This very short flowering time, and perhaps even absence of actual flowers, stamens etc. makes me think whether there is much pollination of the flowers occuring. It seems that many of the tuarts around bunbury have lost their bud caps and there hasn’t really been a flowering event? It will be interesting to see if the flowers have actually been pollinated and produce seed.
I understand that the flower buds might be predated by the tuart bud weevil. So I have been looking for the small holes drilled in the side of the bud cap, and also the offending weevil but haven’t seen any evidence of them.
???? like your comments