Tempting clues in tree rings

[TommyJo]

The most famous solar cycle of all is the Schwabe cycle, with its 11-year cadence.
  But there are other much longer cycles that have well-documented effects on the Earth and its environment.
  However, scientists' attempts to understand the longer cycles were unsuccessful until they learned how the Sun had left some tempting clues in tree rings.

This is an excerpt from an article at https://www.express.co.uk/news/science/1389961/solar-mystery-space-science-tree-rings-sun-schwabe-cycle-evg

Someone can explain the consequences of this discovery in simple language for a beginner.

[Vancanneyt Sander]

We have a 11-year (and 22-year cycle) of the Sun and that we know from 400 years of observations of the Sun by counting the sunspots. This research wanted to go beyond 400 years and go back in time, and they did that with trees. By researching the tree rings for C14, they discovered that there where several years where there was a peak in atmospheric C14 (year 993, 1052 and 1279), this would likely be associated due to solar proton events that can occur during very high solar activity (see our help section for information about space radiation storms). But this doesn't mean that the 11 year cycle is wrong, as no research can tell how many sunspots there where before the observations began. Space radiation storms happen about 50 times per cycle, the more extreme space radiation storms once per cycle. But space radiation storms can only tell that there was significant activity but doesn't tell you anything about the cycle itself (as you can have space radiation storms even before and way after solar maximum).

[Jim Sinclair]

Hi TommyJo,

The website you mention is from a data mining company, their business is to collect personal information about you and me and resell it to advertising companies.

The research they mention has been going on, low key, for many years. I can remember when I was a teenager having a book called, "A star called the Sun" written by George Gamow which included a graph of annual tree growth matched to the sunspot cycles for some trees. I don't think it shows up everywhere and I can't remember where those particular trees were but there are some places in the world where the Schwabe cycle can be seen in climate and growth records.

If rainfall records for the Murray/ Darling basin (Australia) are averaged with a 7 year moving average it is possible to see a 22 year cyclic variation.

Best Wishes,

Jim.