investment ( tectonic lift or volcanic energy ), or to put it another way it was a massive energy investment . And the ongoing maintenance investment is small change ( erosion ), a lower energy investment . The mountain is more durable because the initial investment was very energy costly . But the maintenance investment ( erosion ) is long and typically requires a lot less energy .
By contrast comparatively less energy is invested in growing a tree or a blade of grass , but their ongoing maintenance investment is higher . I ’ m not at all suggesting the investment in a mountain or a tree are equal 11 . I ’ m saying the rate at which Nature turns over its investment is based on the level of initial investment . The rate of maintenance investment for mountain ranges is millennia to centuries ; forests centuries to decades ; and prairies decades to annual . The maintenance investment is based on the energy needed to develop the systems in whole and the rate at which it is expected to turn over and made anew .
But there is a second aspect to the anticipated ROI on the investment Nature makes in building something . When the object or system does eventually succumb to the change ( i . e . when it erodes , decomposes , or turns over , etc .) its
decomposed or eroded state provides the capital for the investment in a new object or system . Those minerals eroding out of the mineral bank of a mountain are being used to feed other types of systems or the development of a new system or object . They might collect along a mountain stream bank and provide the nutrients needed for growing a riparian habitat system . Or maybe those minerals wash all the way to an ocean and feed a marine estuary . Either way , the ROI is recycled as capital into another system or , as in the case of forests and prairies , it is invested on site in perpetuation of the existing system . 12
The two pieces of the ROI work together . Nature doesn ’ t typically invest in relatively low cost systems and then invest costly maintenance energy without still getting something for it . Using our examples , prairie is a pretty low‐cost initial investment , but fires are pretty expensive maintenance investments . Nature gets more from the fire than turning over the prairie . The maintenance investment cost of fire on a prairie , or in a forest for that matter , leads to locking up a LOT of carbon in the soil of the system . A net positive effect for Nature . To put it differently , when Nature does invest in high cost ( energy ) maintenance it ’ s getting a pretty good value for the investment .
11
Nature does apply the basic principle of accounting , credits equal debits , but the accounting at an ecosystem level is really complex .
12
An ecologist once shared with me that it ’ s as if nature was stingy . Once Nature has invested in something it tries to eke out as much value as it can get from its investment .
6 | LEARNING FROM NATURE