Solar shade act in CA
<p>If a neighbors tree that is shading a solar power system that was installed many years ago (2009 homes were built in 2004) in CA (tree might have been existing in a shorter form and the trees grow very quickly), what are the legal obligations of the neighbor to trim the tree?</p>

<p><a href="https://leginfo.legislature.ca.gov/faces/codes_displayText.xhtml?lawCode=PRC&amp;division=15.&amp;title=&amp;part=&amp;chapter=12.&amp;article=" rel="nofollow noreferrer">The Act</a> requires that</p>

<blockquote>
  <p>After the installation of a solar collector, a person owning or in
  control of another property shall not allow a tree or shrub to be
  placed or, if placed, to grow on that property so as to cast a shadow
  greater than 10 percent of the collector absorption area upon that
  solar collector surface at any one time between the hours of 10 a.m.
  and 2 p.m., local standard time.</p>
</blockquote>

<p>The subsequent paragraph pertains to notice that can be given to property owners, and ultimately the tree would be deemable to be a public nuisance and subject to removal. <strong>However</strong> (25984):</p>

<blockquote>
  <p>This chapter does not apply to any of the following:</p>
  
  <p>(a) A tree or shrub planted prior to the installation of a solar
  collector.</p>
  
  <p>(b) A tree planted, grown, or harvested on timberland as defined in
  Section 4526 or on land devoted to the production of commercial
  agricultural crops.</p>
  
  <p>(c) The replacement of a tree or shrub that had been growing prior to
  the installation of a solar collector and that, subsequent to the
  installation of the solar collector, dies, or is removed for the
  protection of public health, safety, or the environment.</p>
  
  <p>(d) A tree or shrub that is subject to a city or county ordinance.</p>
</blockquote>

<p>In other words, if you place a collector where an existing plant can eventually cause shade on the collector (it can be a short tree), you have no remedy. This follows the doctrine of <a href="https://people.ucsc.edu/~wittman/nuisance.html" rel="nofollow noreferrer">coming to the nuisance</a>.</p>

california trees