Ascription is an Anathema to any Enthusiasm

Tree’s don’t get around much, but they still engage extremely syncrhronized behaviors. From time to time all the trees of a given species though out a region will decide to throw a party. These are known as mast years. In these years all the trees in the region will produce vastly more seeds than in other years. It’s an orgy! The distribution of seed production/year is highly skewed with the majority of seeds being produced in these mast years.

I’ve been thinking about power failures, in particularly electrical power failures. Random failures in the power grid pop up all the time, but with surprising regularity large swaths of the power grid fail. I suspect that if you had a plot of the # of customers-days of various failures you’d get a highly skew’d distribution. We know a fair amount of why these grid failures happen. The grid isn’t a grid, it’s a scalefree network. If it were more like a grid then it would be more robust; but a grid is expensive compaired to a scale free network. The grid failures arise because a random failure hits some reasonably key component and then the rest of the grid fails as the problem cascades thru the network.

For example last summer, or the summer before, we had a power grid failure across the megalopolis on the east coast of the North America. The network was running at capacity that hot day when something near Ohio failed. As the load shifted the safety triggers on other components decided that they should resign from the network - to protect themselves. Each resignation accelerated the cascade and soon a hundred million people were without power. I found that interesting at the time because it makes a link between the issues of pure go-it-alone self interested capitalism and the issues of collective good. We have been playing out a recent enthusiasm for handing public goods over to private actors here in the US. These private actors have trouble successfully coordinating the building of enough excess capacity and reliablity into their networks. As the network failures become more likely the individual actors, seeing that their capital equipment is more at risk, tend to shift their safety triggers down; or at least i presume they would.

This year we had a example that’s worse, in it’s way, of a power grid failure. The grid in Queen’s New York failed. This time it appears the the safety triggers were set too high. Again during record load a component failed; but this time as the failures cascaded other components stayed loyal to the network with the result that rather than resign they committed sucide. Which is way bad because to reboot the system they have to pull new cables to replace the ones that burnt out.

Both those models are, to be clear, entirely speculative. But I’d love to know if after the first failure the guys in Queens went around and readjusted thier safety triggers.

The mass years, presumably, are information cascades thru some communication channel the species members have stumbled upon. I bet that when they figure it out they will discover that larger groves of trees play a role in triggering a successfull cascade.

Trees, like other members of the ecology, are embedded in an web of inter-species relationships. Observers have noticed that the mass years throw quite a ripple thru that web. For example squirrel get fat when the oaks have a mass year and then they have lots of offspring - the orgy cascades. The following year though the resulting bubble of population starves. That pattern is actually good for the oaks. The mass year lots of their seeds get past the squirrels. The following year every acorn is found by some desperate squirrel. The third year though the squirrels have dies way back and the oak can again get a lot of acorns past those pests.

I bet there are similar patterns in the supply chain web after each of these power failures. For example I bet there comes season a bit after a large grid failure when you can get a generator really cheap from a vendor who was fat and happy just a season ago.

This entry was posted on Sunday, July 30th, 2006 at 12:43 pm and is filed under economics, natural-world, power-laws and networks. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.