( This ( ( could ( be ( ( the effects ) ( of ( ( an ( 11 ( year cycle ) ) ) ( of ( sunspots ( ( of which ) ( we ( ( are currently ) ( at ( the peak ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT This)) (VP (MD could) (VP (VB be) (NP (NP (DT the) (NNS effects)) (PP (IN of) (NP (NP (DT an) (CD 11) (NN year) (NN cycle)) (PP (IN of) (NP (NP (NNS sunspots)) (SBAR (WHPP (IN of) (WHNP (WDT which))) (S (NP (PRP we)) (VP (VBP are) (ADVP (RB currently)) (PP (IN at) (NP (DT the) (NN peak))))))))))))) (. .)))
This could be the effects of an 11 year cycle of sunspots of which we are currently at the peak.
(ROOT (S (NP (NNS Sunspots)) (VP (VBP occur) (PP (IN in) (NP (DT a) (CD 11) (NN year) (NN cycle)))) (. .)))