* https://lawncaregrandpa.com/how-long-does-grass-live-annuals-and-perennials-explained/
    - Perennial lawn grasses 4-7 years or longer w/ care
    - Northern vs. southern grasses; fall vs. spring sprouting.
* https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2745.2008.01415.x
    - Study of Kentucky grassland
    - Life expectancy of 0.6-0.65 for most perennials at 1 year.
    - Non-grasses more likely to die young.
    - Survival from 1-2 0.11-0.49 (average 0.3) for forbs (non-grasses);
        0.3-0.63 (average 0.44) for grasses.
    - Maximum lifespans 3-25 for forbs and 5-39 for grasses.
    - Type-III survivorship curves, but some forbs almost type-II.
    - Age better than size as survivorship predictor.
* https://prairieecologist.com/2018/06/19/a-closer-look-at-prairie-roots/
    - Grazing naturally removes more-dominant grasses first, increasing
        diversity.
    - Grazed plants also abandon some of their roots (to balance
        transpiration probably?) so that provides more root space for
        other plants.
    - Burn + graze management.
    - Prairie grasses do have very deep roots, but most root mass is in
        first foot or so of soil.
    - Forbs & shrubs pull nutrients from further down in the soil since
        the grasses monopolize what's up top.
    - Ungrazed grasses had thicker roots (more stored carbohydrates not
        needed for re-growth up top?).
* https://prairieecologist.com/2018/08/29/admirable-abundant-and-adaptable-but-not-aggressive/
    - Opportunistic plants like sunflowers grow everywhere when the
        conditions are right one year.
* https://prairieecologist.com/2018/09/25/hubbard-fellowship-blog-olivia-marvels-at-the-persistence-of-plants/
    - Musk thistle produces seeds even if uprooted or sprayed if it's
        already been pollinated.
* https://prairieecologist.com/2014/09/03/konza-prairie-trip-part-2-tree-and-shrub-encroachment/
    - Atmospheric CO2 and agricultural nitrogen are factors in woody
        plant encroachment onto prairies (nearby trees to rain down
        plenty of seeds is another).
    - Long/frequent droughts also favor grasses/herbs over woody
        plants.
    - Estimated fire frequency pre-European encroachment was ~4 years.
    - Shrubs encroached faster when fire frequency was 4 years (almost
        no spread for 1- or 2-year fire areas.
    - Clonal shrubs prioritize spreading horizontally after a fire over
        vertical growth.
    - After tree + shrub growth under 20-year fires, swapping back to
        1-year fires did NOT get rid of the trees + shrubs.
* https://prairieecologist.com/2019/09/17/a-deep-rooted-prairie-myth/
     - Shrub roots help water infiltrate deeper underground where only
         shrubs can access them.
     - Shrubs are more vulnerable to fire because they lose above-ground
         growth tips, while grass growth tips are below ground.
* https://prairieecologist.com/2012/01/04/new-information-on-tree-invasion-in-prairies/
     - Shrubs dominate/invade less in highlands, possibly because
         farther above the water table, their ability to draw on deep
         soil moisture is less of an advantage.
