[HubbardBrook] Hubbard Brook leaf-out forecast for 2022

[Matthew P. Ayres]

Oops. I just noticed a typo in this note.
"As a result of nice work done over the last year by Dartmouth student Elijah Laird, we can add some additional biological insights into the controls on leaf-out phenology at HB. Elijah's analyses for photoperiodic controls provided strong evidence that sugar maple buds become developmentally responsive to degree days on about 20 March, but beech and yellow birch not until about 31 March May."
Matt

From: Matthew P. Ayres
Sent: Sunday, April 3, 2022 13:06
To: Hubbardbrook at lists.sr.unh.edu
Subject: Hubbard Brook leaf-out forecast for 2022

Greetings Hubbard Brook community,
We are pleased to bring good news. Our first phenology forecast for 2022 predicts that spring will come to Hubbard Brook! There are many degree days yet to pass, but if our current forecast holds, leafout on the mid-elevation birds plots (490 m asl) will occur on 11 May, which is about the expected date for 2022 based on historical records (though it has ranged from 2 May to 1 June since 1956).

If you are considering placing any bets based on our phenology forecast, you may wish to consider that last year's forecast was almost a week too early relative to subsequent observations. This was the largest deviation between predicted and observed in 31 years of predictions from our current model (overall root mean square error = 2.5 d). We hope to use the information from this deviation to further refine the phenology models.

As a result of nice work done over the last year by Dartmouth student Elijah Laird, we can add some additional biological insights into the controls on leaf-out phenology at HB. Elijah's analyses for photoperiodic controls provided strong evidence that sugar maple buds become developmentally responsive to degree days on about 20 March, but beech and yellow birch not until about 31 May. This difference will not matter much this year because it was cold during the days of differential responsiveness (accumulation of only 4 degree days > 4 °C during the last 10 days of March).

Based on our current best phenology models (after Lany et al. 2016), temperatures to date this year, and the 10-day forecast as of 29 April 2021, predictions for the mid-elevation bird plot (490 m asl) are:

·       Budburst =11 May,

·       90% completion of leaf expansion = 23 May,

·       Median date of arrival and first clutch initiation for Black-throated Blue Warblers = 13 May and 31 May, respectively.
More details in enclosure.

Feel free to share this with anyone who may be interested. We will aim to provide continuing updates of the forecasts.

Matt

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